SELF-DEFENSE AGAINST ROBOTS -...

SELF-DEFENSE AGAINST ROBOTS

A.MichaelFroomkin†&ZakColangelo††

ConferenceDraft.Pleasedonotquoteorcite.

I. Introduction......................................................................................................................2

II. Self‐HelpAgainstRobots...............................................................................................6A. RobotThreatstoHumans...................................................................................................10B. RobotThreatstoProperty..................................................................................................14C. RobotTrespass.......................................................................................................................151. TrespassinGeneral...........................................................................................................................152. TrespassbyRobots............................................................................................................................17a. DefiningPrivateAirspace...........................................................................................................................21b. WhethertoRequireActualHarm:ConflationwiththeTortofNuisance.............................26

D. InvasionofPrivacybyRobotsasaJustificationforSelf‐Help...............................281. ReasonsforPermittingSelf‐HelpAgainstRoboticIntrusionsonSeclusion..............312. ReasonsforNotPermittingSelf‐HelpAgainstRoboticIntrusionsonSeclusion.....33

III. StatutoryConsiderationsRelatingtoDrones......................................................34A. PotentialFederalAviationAdministrationRegulationofDronePrivacy.........351. CurrentFAAApproachtoDronePrivacyRegulation..........................................................352. ProposedamendmentstoFAAModernizationandReformActof2012....................39

B. StateDrone‐RelatedLegislation.......................................................................................40

IV. ImprovingtheLawofHuman‐RobotInteractions.............................................45A. ClarifyStateRulesonVerticalCurtilage–MakeaNationalRule?.......................45B. ClarifytheRighttoSelf‐DefenseinResponsetoIntrusiononSeclusion...........47C. ReduceUncertaintyaboutRobotsGenerally...............................................................471. ProhibitArmedRobots....................................................................................................................492. GiveNoticeofRobotCapabilities.................................................................................................50a. ExAnteNotice:Warnings...........................................................................................................................51b. ExPostNotice:RobotIdentification......................................................................................................55

3. Recommendation:AMixedApproach.......................................................................................58

V. RobotRightsAgainstPeople.....................................................................................59

Copyright©2014A.MichaelFroomkin&ZakColangelo.AllRightsReserved.

† Laurie Silvers & Mitchell Rubenstein Distinguished Professor of Law, University ofMiami.

††UniversityofMiamiSchoolofLaw,Classof2014.

Self‐DefenseAgainstRobots ConferenceDraft3/19/14

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I. Introduction

Deploymentofrobotsintheair,thehome,theoffice,andthestreetinevitablymeans

their interactions with both property and living things will become more common and

morecomplex.Thispaperexamineswhen,underU.S.law,humansmayuseforceagainst

robotstoprotectthemselves,theirproperty,andtheirprivacy.

IntherealworldwhereAsimov'sLawsofRobotics1donotexist,robotscanpose—

or can appear to pose—a threat to life, property, and privacy.May a landowner legally

shootdowna trespassingdrone?Can sheholda trespassingautonomouscaras security

against damage done or further torts? Is the fear that a drone may be operated by a

paparazzoorapeepingTomsufficientgrounds todisableor interferewith it?Howhard

mayyoushoveiftheofficerobotrollsoveryourfoot?Thispaperaddressesallthoseissues

andonemore:whatrulesandstandardswecouldputintoplacetomaketheresolutionof

thosequestionseasierandfairertoallconcerned.

Thedefaultcommon‐lawlegalrulesgoverningeachof theseperceivedthreatsare

somewhat different, although reasonableness always plays an important role in defining

legal rights andoptions. In certain cases—droneoverflights, autonomous cars—national,

state,andeven localregulationmaytrumpthecommon law. Because it is inmostcases

obviousthathumanscanuseforcetoprotectthemselvesagainstactualphysicalattack,the

paper concentrates on the more interesting cases of (1) robot (and especially drone)

trespass and (2) responses to perceived threats other than physical attack by robots—

perceptionswhichmaynotalwaysbejustified,butwhichsometimesmaynonethelessbe

consideredreasonableinlaw.

Part II discusses common‐law self‐help doctrine, which states that conduct,

otherwisetortious,isprivilegedwhereitcures,prevents,ormitigatesamoreserioustort

1IsaacAsimovintroducedthethreelaws(“1.Arobotmaynotinjureahumanbeingor,throughinaction,allowahumanbeingtocometoharm.2.Arobotmustobeytheordersgiventoitbyhumanbeings,exceptwheresuchorderswouldconflictwiththeFirstLaw.3.ArobotmustprotectitsownexistenceaslongassuchprotectiondoesnotconflictwiththeFirstorSecondLaw.”)inRunaround,ashortstoryoriginallypublishedintheMarch1942issue ofAstounding Science Fiction and subsequently included in ISAAC ASIMOV, I ROBOT(1950).


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thatis,orreasonablyseemstobe,abouttooccur.Intheprotection‐of‐personcontext,the

issueissimplebecausewevaluelifemorethanproperty.Onemaydestroyevenexpensive

propertyinthereasonablebeliefthatthedestructionisnecessarytosaveone'sownlifeor

that of another. The same general rule applies to non‐life‐threatening personal injury,

subjecttoareasonablenesstestastotherelativedamages.Ontheotherhand,onemaynot

destroyexpensivepropertytoprotectinexpensiveproperty.Thetestisoneofcost‐benefit:

thechattelthatposesthethreatmaybeharmedonlyifthecostofthatharmislessthanthe

costoftheharmthatwillotherwisebedonebythechattel.

Privacyintrusionscomplicatethecalculus.Intrusionuponseclusionisarecognized,

ifsomewhatexotic,tort,butitsrarityinthecourtsmeansthatthescopeofpermissibleself‐

help against privacy‐invading chattels—like the camera planted by the landlord in the

tenant'sbedroom—ispoorlychartedlegalterritory. Inprinciple,atort isatort,sosome

self‐helpshouldbejustified.

In Part II.D we argue that the scope of permissible self‐help in defending one's

privacy should be quite broad. There is exigency in that resort to legally administered

remedieswould be impracticable; andworse, the harm caused by a drone that escapes

withintrusiverecordingscanbesubstantialandhardtoremedyafterthefact.Further,itis

commonfornewtechnologytobeseenasriskyanddangerous,anduntilprovenotherwise

dronesarenoexception. At least initially, violent self‐helpwill seem, andoftenmaybe,

reasonableevenwhentheprivacythreatisnotgreat—orevenextant.OneColoradotown

hasalreadyproposedtoofferdrone‐huntinglicensesandabountyforthoseshotdown.2

Alimitingprinciple,however,isthattheintrusion‐upon‐seclusiontortrequiresthat

theintrusionbehighlyoffensivetoareasonableperson.Andself‐helpislimitedtowhata

reasonablepersonwouldthinknecessary.Thecalculus,then,mustbalancethevalueofthe

interestbeingprotectedagainstthevalueofthechattelcommittingtheintrusionandthe

riskofharmtothirdparties.Third‐partyrightscouldmakeitunreasonabletoshootator

disable a drone, as the projectile or the falling drone could injure bystanders or their

property.

2Seeinfratextaccompanyingnotes98‐100.


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That calculation may ask too much. Unlike defending life or property against a

chattel, defending privacy against a chattel requires a cost‐benefit analysis that may be

impossible to make in the abstract or the particular: A person cannot reasonably be

expectedtoknowmuchaboutanintrudingdrone'scapabilitiesorintentions;hencethreat

assessment,much lessbalancing, isnearly impossible;does that justify theuseofpurely

precautionary self‐help? In addition, the calculation demands a value judgment about

privacy, and invites inquiry intowhat sortsof self‐help shouldbepermitted, rather than

justwhethertherobotlooksmoreexpensivethanthepropertytobedefended.

Furthercomplicatingmatters,statecommon‐lawcanbepreemptedbyfederaland

statelegislationandregulation.PartIIIthereforeoutlinessomerelevantstateandfederal

lawandexplainshowitinfluencespartsoftortlaw.TheFederalAviationAdministratino

(FAA)regulateshowlowfixed‐wingaircraftandhelicoptersmay lawfully fly,andsimilar

rulesfordronesarelikely. Theseruleshelpdefineatrespass. Butwhileheightrulesare

likely,federalactionintheprivacyarenaisnot.Statelegislationandcommon‐lawruleswill

thus continue to play a fundamental role in shaping individuals’ privacy rights. Several

states have passed legislation regulating private and public drone use, often evincing a

concernforprivacyrights.

PartIVcontainsourrecommendationstosolve,oratleastameliorate,sevenissues

we identifyduringour surveyof current law inParts II and III.The seven issues canbe

summarizedasfollows:

1.Becausebothself‐defenseanddefenseofanotherpersonareprivilegedwhena

mere chattel reasonably appears to present a physical threat,3some peoplemay be too

willing to destroy robots when they feel threatened by them, and the law will tend to

permitthis;

2. Becauseitwillbedifficultfortheaveragepersontoknowthecapabilitiesofan

unfamiliar robot—something essential tomaking good judgments of howdangerous the

robotmightbe—somepeoplewillover‐protecttheirpropertyagainstdamagefromrobots.

What ismore, so long as this uncertainty about robot danger (whether as a class, or in

3Seeinfrra§II.A.


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specificcasesofambiguouslydangerousrobots)iswidespread,tortlawwilltendtotreat

thisover‐protectivebehavioras“reasonable”andthusprivileged;4

3.Relatedly,thegreatdifficultiesinassessingtheprivacyconsequencesofarobotic

intrusionwill also leadpeople to err—reasonably—on the side of caution and thus self‐

help.Totheextentthattortlawrecognizesarightofself‐helpagainstprivacyintrusions,5

thelawwilltendtoprivilegethatconductalso;6

4.. These considerations will apply evenmore strongly to aerial robots (drones):

peoplewillhavesignificantpracticaldifficulties in identifyingandassessing theposition,

actions, and capabilities of aerial robots. The resulting uncertainty will make some

propertyownerstoowillingtotakeoffensiveactioninperceivedself‐defense.Tortlawis

likely to be solicitous of the property‐owner’s need to make quick decisions under

uncertainty. That solicitude will not, however, extend to actions that presented a

reasonableriskofdangertothirdparties,suchasshootingintotheairinpopulatedareas.7

5.There isuncertaintyas to theverticalperimeterofproperty,8somethingpeople

will need to know in order to determine when an aerial robot is committing a legal

trespass.

6. The law is unclear as to the extent of the privilege for self‐help in the face of

privacytortslikeintrusionuponseclusion.9

7.Undertortlawprinciples,aperson'sprivilegetodefendherpropertybyharming

arobotreasonablyperceivedasdangerouswillturnonthevalueoftherobotasmuchas

onthevalueofthepropertybeingthreatened.Apersoncanbeexpectedtoknowthevalue

ofthepropertysheisprotecting,butthelawwillrecognizethatitwillbedifficultforthe

canonical ordinary reasonableperson tomake an estimateof a robot's value in a timely

mannerduringanemergency.10Ifcourtsattempttorelyonthereasonablyperceivedvalue

of the robot, then that creates incentives for robot designers tomake their robots look

4Seeinfra§§II.B,II.C.5Seeinfra§II.D.6Seeinfra§§II.C,II.D.7Seeinfratextaccompanyingnote72.8Seeinfra§II.C.2.a.9Seeinfra§II.D.10Seeinfra§II.B.


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more expensive than they are. Encouraging gilding of robots in order to make them

resistanttoself‐defensepredicatedontortclaimsofpropertydamageseemsundesirable.11

Ourproposedsolutionstotheseproblemsbeginwiththeobservationthatmostof

these problems spring from some kind of uncertainty about, or relating to, robots. We

therefore suggest measures to reduce those uncertainties, ranging from forbidding

weaponizedrobotstorequiringlights,andothermarkingsthatwouldannouncearobot’s

capabilities, andRFID chips and serial numbers thatwould uniquely identify the robot’s

owner.

Part V concludes with a brief examination of what if anything our survey of a

person'srighttodefendagainstrobotsmighttellusaboutthecurrentstateofrobotrights

againstpeople.

II. Self‐HelpAgainstRobots

Robotsposeathreatofphysicalharmtolifeandlimb.Google’sautonomouscarmay

runoveryour footasyoucross thestreet;Amazon’sdronemaydropapackageonyour

head.Robotsalsoposeaphysicalthreattoproperty:thecarorthepackagemayhityour

car insteadofyou.Robotsmaytrespass,harmingyou inyour technicalright toexclusive

possession. Drones, like manned aircraft, will crash, and should Google Maps provide

misinformation,theautonomouscarmaymakearightturnontoyourfrontlawn.Finally,

robotsposeathreattoprivacy.Theymayspybyrecordingorinterceptinginformationin

situationswhereitwouldbedifficultforahumantodoso.

As technology enables new ways for individuals and their mechanical agents to

committorts, the lawmustrespond.Robotspresentquestionsthat inmanycaseswillbe

answeredbyappealtoclassiclegalrules.Butrobotssometimesmayalsorequirenewrules

ornewunderstandings.Onemightsometimesavoidtheneedforself‐defensebyreasoning

11OurproposalsinPartIVaddresseachofthefirstsixissuesabovedirectlybuttheydonot directly confront this seventh issue. However, by reducing the number of cases inwhich people erroneously become convinced they need to defend themselves against arobot our proposals at least address this issue indirectly in that it will matter lessfrequently.


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withahumanwhoappearspoisedtocommitatort12butthatstrategymaynotworkwitha

robotlackingcognition.Forcewillsometimesbethebestoptionindealingwithanout‐of‐

control robot; even when force is not obviously the best choice, people will sometimes

resorttoitnonetheless.Thelawmustbepreparedtoaddresstheseinevitablescenarios.

The law calls this use of defensive force “self‐help.” Tort self‐help “is any

extrajudicial act that cures, prevents, orminimizes a tort.”13Traditionallywedistinguish

between two typesof self‐help: simpleself‐help, inwhich theself‐helper’sactions inany

eventwouldbelegal,andthespecialcasewheretheself‐helper’sactionsarejustifiedonly

because of the danger imposed by the tortfeasor. In the simple case, the self‐helper’s

conductrequiresnospeciallegalprivilege.Examplesofthislegallystraightforwardtypeof

self‐helpincludestayinginsideatnighttopreventrobberyanderectingafencetoprevent

trespass.Othertypesofconductthatwouldnormallybetortiousorotherwisesanctionable

become legal when justified by special circumstances such as the risk imposed by the

tortfeasor’s act or omission. Deemed “coercive self‐help” by Richard Epstein,14these

actionsarepermissibleonlybecauseofalegalprivilege.15

We focus on self‐help against the torts that mobile robots seem most likely to

commitinitially,namelyassault,battery,trespass,andinvasionsofprivacy.Inthelongrun,

as robots become more sophisticated and autonomous, we may see robots committing

conversionorevenfraud,butwe leavethose foranotherday. Inordertodeterminethe

extent towhich people have common‐law right to defend themselves against robotswe

mustbeginbylookingataperson’srightofself‐defenseagainsttortsbyotherpeople,and

12W.KEETONPAGEETAL.,PROSSERANDKEETONONTORTS132(5thed.1984)(“Ordinarilytheuse of any force at all will be unreasonable unless the intruder has first been asked todesist.Blowsarenotjustifiedwhereitisnotclearthatwordsalonewouldnotbeenough.”).This isnot thecase in the robot context.Negotiationwillneverwork, so theprivilegeofself‐helpshouldbecorrespondinglybroaderthanelsewhere.

13Douglas Ivor Brandon et al., SpecialProject:Self‐Help:ExtrajudicialRights,Privilegesand Remedies in Contemporary American Society, 37 VAND. L. REV. 845, 852 (1984)(hereinafterVanderbiltSpecialProject).

14RichardA.Epstein,PropertyRightsontheFrontier:TheEconomicsofSelf‐HelpandSelf‐DefenseinCyberspace:TheTheoryandPracticeofSelf‐Help,1J.L.ECON.&POL'Y1,3(2005).

15Alegalprivilegeis“conductwhich,underordinarycircumstances,wouldsubjecttheactor to liability, [but] under particular circumstances does not subject him to suchliability.”RESTATEMENT(SECOND)OFTORTS§10(1965).


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thenataperson'sunilateral right toharmanotherperson'schattelswhen thosechattels

threatenpeopleorproperty. There isnocategoryof “robot torts”becausemachinesare

notconsideredtobethelegalauthorsoftheiractions,justascomputersarenotheldliable

for their own acts or omissions.16 Nevertheless, throughout this paper we adopt that

shorthandontheunderstandingthatthelawwilllookbehindtherobottofindapersonto

holdliablefortherobot'sactions.17

Usually a person who has been wronged is expected to go to law for redress.

Indeed, it is common to claim that one of the hallmarks of modern civilization is that

personal revenge and vendetta have been displaced by due process and state‐controlled

remedies.18Incontrast,self‐helpispersonalandextrajudicial.Nevertheless,two19factors

justifycarvingoutaself‐helpprivilege.20First,thelawrecognizesthatthejudicialremedies

16For an early and accurate prediction that “for the foreseeable future” computerswould not be held liable for their acts and omissions see John F. Banzhaf III,When aComputerNeedsaLawyer,71DICK.L.REV.240,240(1967).Forageneraldiscussionofhowtort law might one day account for autonomous robots, see Curtis E.A. Karnow, TheApplication of Traditional Tort Theory to Embodied Machine Intelligence,http://works.bepress.com/curtis_karnow/9.

17There will undoubtedly be interesting issues as to which of the various partiesinvolvedinthedesign,construction,programming,andoperationofarobotshouldbeheldresponsible for harm it causes. Those questions, however, are beyond the scope of thispaper.

18SeeVanderbiltSpecialProject,supranote13,at853(“Theearliesttortremedieswereexclusivelyself‐help.Earlymedievalplaintiffs,withoutcourtsonwhichtodependorwithonlyafewcourtsoflimitedjurisdictiontowhichtheycouldturn,oftenhadtoseekredressdirectlyfromthetortfeasororhisfamily,usuallybyforceofarms.Thisadhocsystemoftenled tobreachesof thepeaceand,notuncommonly,bloodshed.Exclusiverelianceonself‐helpalsogavethestrongestmembersofsocietyadisproportionateabilitytorecoverandled to an inequitable distribution of remedial fruits. These concerns and the desire tocentralize economic and judicial power causedmedieval rulers to establish a system ofcourts that generallydiscouraged self‐help, especially in the tort field.One commentatorhasdescribedthe‘firstbusinessofthelaw,andmoreespeciallyofthelawofcrimeandtort’offifteenthcenturycourtsasthesuppressionofself‐help.”)(footnotesomitted).

19Other minor factors also come into play. For example, traditional ideas of thereasonablenessofinstinctivehumanreactionsalsocontributetothepermissivenatureofthe self‐help privilege. SeeVanderbilt Special Project, supranote 13, at 853 (“To ask aninnocent party . . . to refrain from the use of forcewhen threatenedwith serious bodilyharmorthesubstantiallossofpropertyistodemandtoomuch,andincreasethechancesof[theinitial]aggression.”).

20SeeVanderbiltSpecialProject,supranote13,at853.


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availablemaysometimesbeinadequate,orself‐helpremediessuperior.21Second,thelaw

recognizes that in certain circumstances the use of self‐help will only minimally impair

society’sinterestinlawandorder.22Thelawiswillingtopermitextrajudicialremediesof

anactor’sownmakingwhereajudicialremedyisinconvenientorunavailable,andwhere

self‐helpdoesnotstronglythreatenabreachofthepeace.

Common‐lawself‐helpdoctrinegenerallyboilsdowntoareasonablenessstandard.

In general, threats to persons may be met with proportionate counter‐violence.23 But

threats toproperty, especiallymeager threats like technical trespass, cannot in themain

justifyharmstopersons.24Apropertyownermaydefendhispropertyonlywithsuchsteps

as societyviewsas reasonablynecessary.25 In the classic common lawcases, thismeant

that potentially lethal self‐help was rarely allowed just to protect against threats to

property.26Thatstandardhasbeenmodifiedbystatute.27Thus thekey issue inmapping

21RichardEpsteinnotesasanexamplethatnooneisforcedtopayforgoodsthathavenot been delivered. “It would be grotesque to foreclose that option and to force theinnocent party to sue in contract for expectation damages. The innocent party gets theoptions.”Epstein,supranote14,at26.

22SeeVanderbiltSpecialProject,supranote13,at853.23SeeRESTATEMENT(SECOND)OFTORTS §§ 63‐66 (1965); RESTATEMENTOFTORTS§§ 63‐66

(1934).24See,e.g.,Andersonv.Smith,7Ill.App.354,358(Ill.2dDist.Ct.App.1880)(notingthat

because the lawplaces “sucha transcendentvalueuponhuman life . . . [,] it conclusivelypresumesthat it isnotreasonableto takethe lifeofahumanbeingwhenthethreatenedinjury,ifconsummated,wouldbebutameretrespassormisdemeanor.”);seegenerallyW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS133‐34(5thed.1984)(“Eventhetraditionthataman’shouseishiscastle,andthatonemaykillindefenseofhisdwelling,hasgivenway inmost jurisdictions to theview that such force isnot justifiedunless the intrusionthreatens thepersonal safety of the occupants.”) (footnotes omitted);RichardA. Posner,KillingorWoundingtoProtectaPropertyInterest,14J.L.&ECON.201(1971).

25SeeRESTATEMENT(SECOND)OFTORTS§260(1965)(“[O]neisprivilegedtocommitanactwhich would otherwise be a trespass to a chattel or a conversion if the act is, or isreasonably believed to be, necessary to protect the actor's land or chattels or hispossessionofthem,andtheharminflictedisnotunreasonableascomparedwiththeharmthreatened.”);id.at§263(“Oneisprivilegedtocommitanactwhichwouldotherwisebeatrespasstothechattelofanotheroraconversionofit,ifitisorisreasonablybelievedtobereasonableandnecessarytoprotectthepersonorpropertyoftheactor....”).

26See,e.g.,Bird v.Holbrook, (1828) 130Eng.Rep. 911 (C.P.) (imposing liability on anownerwho left a spring gun to injure a trespasser);seealsoRESTATEMENTOFTORTS § 79(1934) (recognizing privilege to use deadly force in defense of property only where


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the scope of permissible self‐help against robots will be defining the harm posed by a

tortfeasing robot: the threat of limited harms justifies only limited self‐help remedies,

whilegreatharmsmayjustifyuniqueandsevereself‐helpremedies.28

A. RobotThreatstoHumans

We see both classic justifications for self‐help in the paradigmatic example of the

self‐help privilege. Theuse of violence to protect one’s bodily integrity is privileged, i.e.,

permitted,becausejudicialremediesarenotavailableduringameleeandbecausesociety’s

interestinmaintainingorderisnotappreciablyharmed.Judicialremediesareinadequate

whensomeoneisbeatingyouontheheadbecauseordinarilyavictimofaphysicalbattery

doesnothavetheluxuryoftimetogotocourttoseekaninjunctionagainstit.And,while

privileging the application of force in self‐defense does risk breaching the peace, the

damagehasinsomesensealreadybeendonewhentheinitialattackerbreachedthepeace;

allowing the invocation of a self‐defense privilege will not in most cases make matters

notablyworse.

necessarytoprotecttheoccupantfromdeathorseriousbodilyharm).ButseeScheurmanv. Scharfenberg, 50 So. 335 (Ala. 1909) (recognizing privilege to use potentially deadlyforce in defense of business premises). The privilege to use non‐deadly force, such asbarbedwire,toprotectpropertyismoregenerallypermissible.SeeRESTATEMENTOFTORTS§84(1934).Oneofthecommentstothatsectionstatesthattheprivilegeisnotdestroyedbytheuseofadevice“whichis likelytodomoreharmthanthepossessorof landwouldbeprivilegedtoinflictifhewerepresentatthetimeoftheparticularintrusion.”Id.atcmt.e.

27See,e.g.,FLA.STAT. § 782.02 (2013) (“The use of deadly force is justifiable when apersonisresistinganyattempttomurdersuchpersonortocommitanyfelonyuponhimorheroruponor inanydwellinghouse inwhichsuchpersonshallbe.”);CAL.PENALCODE§197(West,WestlawthroughCh.1of2014Reg.Sess.)(“Homicideisalsojustifiablewhen...committed indefenseofcommitted indefenseofhabitation,property,orperson,againstonewhomanifestly intendsorendeavors,byviolenceorsurprise, tocommita felony,oragainst one who manifestly intends and endeavors, in a violent, riotous or tumultuousmanner, to enter the habitation of another for the purpose of offering violence to anypersontherein....”).

28See,e.g.,Hummelv.State,99P.2d913(Okla.Crim.App.1940)(recognizingprivilegeto castrate mongrel bull where it threatened to impregnate thoroughbred cattle);McKeesportSawmillCo.v.PennsylvaniaCo.,122F.184(C.C.W.D.Pa.1903)(statingindictathat railroad might be justified in taking more extreme measures than an ordinarylandownerbecauseofitspublicdutiesandtheuniqueharmposedbyobstructionsonthetracks).


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Asageneralmatterhumansmayonlyusereasonableforceagainstotherpeopleto

protectthemselvesagainstfromphysicalharmincludingbothassaultandbattery.29When

humansareendangeredbyproperty,thequantumofforcepermittedagainstthatproperty

ismoreexpansivethanwhenapersonisthreateningtheharm30butstillnotunlimited.31

Onemaydestroyevenexpensiveproperty inthereasonablebeliefthatthedestructionis

necessary to save one’s own life or that of another.32The same general rule applies to

defense against non‐life‐threatening personal injury (battery), and the reasonable

apprehensionofphysicalinjury(assault),subjecttoareasonablenesstestastotherelative

damages.33

AtpresentunderthelawofallU.S.jurisdictions,allrobots,nomatterhowcleveror

autonomous, are property.34Thus, under these standard tort principles, in any case in

which a robot reasonably appears to threaten human life or even threatens to commit

29RESTATEMENT OF TORTS §§ 63‐66 (1934); RESTATEMENT (SECOND) OF TORTS §§ 63‐66(1965).

30See,e.g., Pennsylvania v. Baker, 74 Pa. D & C. 2d 595, 600 (C.C.P. Pa. 1975) (“Thepersonunderattackwillnotbeheldtothesamestandardofjudgmentinshootingadogashewouldbeinshootingahuman,eveninself‐defense.”).

31Thus, an individual is not privileged to destroy a Rembrandt in order to prevent amerebumponthetoe.Thisfollowsfromthegeneralreasonablenessstandard:thethreat(bump on the toe) must be of the sort that requires immediate action. And the action(destruction) must be reasonable in light of both the harm it will cause (value ofRembrandt)andtheharmitwillprevent(bumpontoe).Whereareasonablepersonwouldtake the bump on the toe rather than destroy the property, the law will not allow theunreasonable behavior; consequently the person attached to the toe must pay for theRembrandtifsheharmsit.SeeW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS136(5thed.) (“The conduct of the defendant in preventing the harmwould be unreasonable if areasonablepersonwouldnotsoactbecausethemagnitudeoftheharmthatwouldlikelyresultfromtheactionoutweighedthebenefitsoftheaction.”).

32RESTATEMENT OF TORTS § 261 (1934) (“One is privileged to use or otherwiseintentionally intermeddlewith a chattle in the possession of another for the purpose ofdefendinghimselforathirdperson....”).

33RESTATEMENT(SECOND)OFTORTS§§63‐64(1965)(addressingdefendingagainstpersonthreatening tocausenon‐life‐threateningpersonal injury);RESTATEMENT(SECOND)OFTORTS§ 261 (1965) (addressing defending against chattel threatening to cause non‐life‐threateningpersonalinjury).

34JusticeOliverWendallHolmesdefined“property”asanythingforwhichthereexistsamarket,i.e.,anythingtreatedaspropertyoveranextendedperiodoftime.ThePathoftheLaw,10HARV.L.REV.457,476‐77(1897).


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seriousbodilyinjury,notonlythepotentialvictimbutalsothirdpartieswillbejustifiedin

destroyingtheoffendingrobot.Atthesametime,theoverarchingreasonablenessstandard

meansthatpeoplewillnotbejustifiedindestroyingarobotthatappearstobethreatening

apersoniftheself‐helperkneworshouldhaveknownthattheapparentvictimwasnotin

fact in danger, or if the self‐helper knew or should have known of a feasible and less

destructive means of preventing the human injury. But even here the law makes

allowancesforthepressureimposedbytheneedforsplit‐secondjudgments,andthusdoes

notrequireperfectdecisionmakingfrompotentialvictimsorrescuersinemergencies.35

In light of thenewnessof robotic technology, an alternate legal theory fordrone‐

operator liability, andperhaps robot‐operator liabilitymoregenerally,wouldbea strict‐

liability regime on the grounds that robot use in public is an ultrahazardous activity.

Ultrahazardousactivities—likeusingdynamiteinconstructionorkeepingwildanimalsas

pets—aresubjecttostrict liability36toensurethatsuchactivitiesareundertakenwithall

appropriateprecautions.Theverydangerousnessofanultrahazardousactivitymeansthat

self‐defenseagainstitsharmfulconsequenceswillusuallybeprivileged.37Whenairplanes

werenewandexperimental,theirusewasconsideredanultrahazardousactivityandwas

subject toa strict‐liability regime.38The rationalewas thatairplaneswere (1)dangerous

35See,e.g.,Andersonv.Smith,7Ill.App.354,360‐61(Ill.2dDist.Ct.App.1880)(“Weusethewordsapparentdangerbecausewedonotconsiderthatrealdangerisindispensibleindefenseofproperty,anymorethanit is indefenseofperson.Ineithercaseapartymustjudgeofandactfromtheappearances.”);seegenerallyW.PageKeeton,etal.,ProsserandKeetononTorts125(5thed.1984) (“Theprivilege toact inself‐defensearises,notonlywherethereisrealdanger,butalsowherethereisareasonablebeliefthatitexists.”).

36Strictliabilityistheoppositeoffault‐basedliability—itimposesliabilityevenabsentnegligenceorintenttoharm.Inthatwayitimposesanabsolutedutytonotcauseharm.

37This again follows from the general reasonableness standard because the harmthreatenedbyultrahazardousactivitiesissosevere.

38SeeRESTATEMENTOFTORTS § 520 cmt. g (1934) (“[A]viation has not as yet becomeeitheracommonoranessentialmeansoftransportation.This,coupledwiththefactthatasyetaeroplaneshavenotbeensoperfectedastomakethemsubjecttoacertaintyofcontrolapproximating that ofwhich automobiles are capable, andwith the serious character ofharmwhichanaeroplaneoutofcontrolislikelytodotopersons,structuresorchattelsonthelandoverwhichitfliesmakeitpropertoregardaviationasanultrahazardousactivity.Furthermore, a perfect plane perfectly flown may crash in unfavorable weatherconditions.”);RESTATEMENT(SECOND)OFTORTS§520A(1965)(“Ifphysicalharmtolandortopersonsorchattelsonthegroundiscausedbytheascent,descentorflightofaircraft,orby


13

and(2)uncommon.39In thatway,airplanesweredistinct fromautomobiles,whichwhile

perhapsmoredeadlyweresignificantlymorecommon.Unarmedrobots,includingdrones,

areprobablynotasdangerousasmannedaircraftwereintheearlytwentiethcentury,and

whetherdronesareasdangerousasawildanimalkeptasapetwillprobablydependon

the characteristics of the individual robot. Thus it is not clear that the operation of the

ordinaryrobot—oreventheordinarydronethat iscapableof fallingoutofthesky—will

qualify as anultrahazardousactivity. Robots are, however, still somewhatuncommon—

althoughtheimpetusforthispaperisthepredictionthatrobotswillbecomecommonsoon.

Thus, although it is possible that courts might treat the operation of robots with the

capability to hurt people as an ultrahazardous activity for an introductory period, we

wouldnotexpectthatperiodtolastlong,atleastasregardsrobotsthatdonotcarryanti‐

personnelweapons.RemotelycontrolleddronesoutfittedwithgunsorTasersmightwell

be considered ultrahazardous, especially if there is any risk that theymight be hacked,

hijacked, or malfunction. Semi‐autonomous weaponized robots could easily qualify as

ultrahazardous, and fully autonomous armed robots would be considered even more

dangerous.

the dropping or falling of an object from the aircraft, (a) the operator of the aircraft issubjecttoliabilityfortheharm,eventhoughhehasexercisedtheutmostcaretopreventit,and (b) the owner of the aircraft is subject to similar liability if he has authorized orpermittedtheoperation.”);TimothyM.Ravich,TheIntegrationofUnmannedAerialVehiclesIntotheNationalAirspace, 85N.D.L.REV.597,603 (2009) (noting that “an early view ofaviation—whetherbyballoonorbysomethingelse—[was]asanultrahazardousactivity”);P.F.Boherty,TortsinAeronauticalNavigation,19Temp.L.Q.496,496(1946)(notingthatattheendof1945,eighteenstateshadarule“provid[ing]thattheownerand/oroperatorofeveryaircraftwhich isoperatedover landorwaterof thestate isabsolutely liable forinjury topersonsorpropertyonthe landorwaterbeneath . . .whethersuchownerwasnegligentornot”).

39See RESTATEMENT OF TORTS § 520 (1934) (“An activity is ultrahazardous if it (a)necessarilyinvolvesariskofseriousharmtotheperson,landorchattelsofotherswhichcannotbeeliminatedbytheexerciseoftheutmostcare,and(b)isnotamatterofcommonusage.”);RESTATEMENT(SECOND)OFTORTS§520(1965)(“Indeterminingwhetheranactivityisabnormallydangerous,thefollowingfactorsaretobeconsidered:(a)existenceofahighdegreeofriskofsomeharmtotheperson,landorchattelsofothers;(b)likelihoodthattheharmthatresultsfromitwillbegreat;(c)inabilitytoeliminatetheriskbytheexerciseofreasonable care; (d) extent to which the activity is not a matter of common usage; (e)inappropriatenessoftheactivitytotheplacewhereitiscarriedon;and(f)extenttowhichitsvaluetothecommunityisoutweighedbyitsdangerousattributes.”).


14

B. RobotThreatstoProperty

Incontrasttowhenapersonisthreatened,inwhichcaseevenexpensiveproperty

canbedestroyedtosavelifeandlimb,onemaynotdestroyexpensivepropertytoprotect

inexpensiveproperty.40Thetestisoneofcost‐benefit:thechattelthatposesthethreatmay

be interferedwithonly if theexpectedcostof that interference is less than theexpected

costoftheharmthatwillotherwisebedonebythechattel.41

Ifapersonmaynotdestroyexpensivepropertytoprotect inexpensiveproperty it

follows that a person’s right to self‐help will be greater against an inexpensive‐looking

robot threating property damage than against an expensive‐looking robot threating the

samedamage.42Thedifficulty, however, is that thisdistinctiondependson theproperty‐

ownerhavingsomesenseofwhat therelativevalueof therobot is. Thecourts longago

decided that decisionmakingunder stress neednot be perfect. As one court put it, if a

chicken‐ownerwasprivileged to shoota trespassing,hungrydogonly if thevalueof the

propertyheprotectsisinfactgreaterthanthevalueofthedog,then“akeeperofpoultry

mightlosehisentireflockofchickenswhileendeavoringtoascertainwhethertheattacking

dogwasworthmorethanthechickens,andthusbedeprivedoftheright,whichthelawhas

givenhimfromtheearliesttimes,todefendhispropertyagainsttheunlawfulactsofman

orbeast.”43

That expensive robots enjoy more protection than inexpensive ones may create

perverse incentives for drone owners and operators: apparently one can increase the

protectionenjoyedbyone’srobotbymakingitlookmoreexpensivethanitactuallyis.

40Cf.RESTATEMENT(SECOND)OFTORTS§260(1965)(notingthatthe“harminflicted[mustnotbe]unreasonableascomparedwiththeharmthreatened).

41See,e.g.,Nesbittv.Wilbur,58N.E.586,586(Mass.1900)(holdingthatwhetheraself‐helperisjustifiedindefendingherpropertydepends“uponanumberofvariablefacts—theimminenceandnatureoftheharmthreatened,thekindofpropertyinperil,fromwhomorwhat the danger proceeds, the relative importance of the harm threatened, andwhat isdoneindefense”).

42Cf.W.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS136 (5thed.) (“Theconductofthedefendantinpreventingtheharmwouldbeunreasonableifareasonablepersonwouldnot so act because the magnitude of the harm that would likely result from the actionoutweighedthebenefitsoftheaction.”).

43Johnstonv.Wilson,123S.E.222,224(Ga.Ct.App.1924).


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C. RobotTrespass

We turn now to the more complicated cases of robot (and especially drone)

trespass.

1. TrespassinGeneral

A trespass is an intentional entry onto an owner’s land or property without her

permission.44Trespassisastrict‐liabilitytort,meaningthatdefendantsareliableevenin

theabsenceofanynegligenceontheirpart.45Trespassisactionableevenwhenaccidental.

Oneneedonlyintendtoenterthelandtocommitatrespass,andmaybeliableevenabsent

knowledge that the property is ownedby another. Furthermore, unlikemost other torts

whereplaintiffsmusthaveandproveactualdamages inordertohaveaviableclaim,the

trespass plaintiff does not need to prove actual damages to the property. As a formal

matter,althoughnotsomuchinpractice,thesimpleviolationofthetechnicallegalrightto

exclusivepossessionisharmenoughinandofitselftojustifyalawsuit.46

Unlike in cases of actual physical harm—where damage includes a physical base

that is calculable, monetizable, and thus susceptible to cost‐benefit analysis—the less‐

tangibleharmtotechnicallegalrightsincasesoftechnicaltrespassdoesnotlenditselfto

straightforwardcost‐benefitbalancing.Thesimplestcaseiswhenthetrespasshascaused

onlynominaldamages—justgrassthathasbeentroddendown.Iftheintruder’sdamageis

small, it follows that the self‐help reprisal must be small too, or else it exceeds the

privilege.47

44RESTATEMENT (SECOND) OF TORTS § 158 (1965); RESTATEMENT (THIRD) OF TORTS § 50(2012).

45RESTATEMENT (SECOND) OF TORTS § 158 (1965); RESTATEMENT (THIRD) OF TORTS § 50(2012).

46Trespassprotectstherightofexclusivepossession,notmerelythetangiblepropertyitself.RESTATEMENT(THIRD)OFTORTS§50(2012)(“Atrespasser isapersonwhoentersorremainsonlandinthepossessionofanotherwithoutthepossessor’sconsentorotherlegalprivilege.”).;RESTATEMENT(SECOND)OFTORTS§158(1965)(“One[maybe]subjecttoliabilityto another for trespass, irrespective of whether he thereby causes harm to any legallyprotectedinterestoftheother....”).

47Cf.RESTATEMENT(SECOND)OFTORTS§260(1965)(notingthatthe“harminflicted[mustnotbe]unreasonableascomparedwiththeharmthreatened).


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Tortlawrecognizesasactionabletrespassesbychattelswhenanindividualcausesa

chattel to enter or remain on land in the possession of another.48So when inanimate

chattelssuchcars,49orconstructionequipment50cometorestona landowner’sproperty,

thegeneral rule is that the landowner is entitled to remove the trespassing chattels, but

maytakeonlysuchstepsasarereasonablynecessarytoeffecttheremoval.51Theprivilege

(to interferewithanother'schattel) isnarrowherebecause it is triggeredbyarelatively

insignificantharm.

Specialrulesinanimalcasesaddanadditionalwrinkle:ifthelandowneriswillingto

give theanimalsproper care, shedoesnothave to remove them. Instead shemayseize

them and bill their owner for the nominal damages from the trespass and the costs of

caring for the animals (in part because the seizure prevents additional damage to the

property or vegetation).52Often granted today by estray53statutes,54the right to capture

andholdassecuritytrespassinganimalsderivesfromtheancientlegalremedyofdistraint

48RESTATEMENT(SECOND)OFTORTS§158(1965).49Rossiv.VentrescaBros.Const.Co.,405N.Y.S.2d375(CityCt.1978);Reedv.Esplanade

Gardens,Inc.,398N.Y.S.2d929(City.Ct.1977).50Melbourne Bros. Constr. Co. v. Pioneer Co., 384 S.E.2d 857 (W. Va. 1989); Sears v.

Summit,Inc.,616P.2d765(Wyo.1980)(recognizingprivilegebutfindingitexceeded).51See RESTATEMENT (SECOND) OF TORTS § 260 (1965); see also Note, Torts—Property

AccidentallyCastonLandofAnother—UnnecessaryDamage inRemoval, 27 YALE L.J. 569(1918); Grier v. Ward, 23 Ga. 145 (1857) (holding that the landowner could remove,without causing unnecessary injury, cotton placed on his property without hisauthorization, and stating in dicta that the cotton‐owner might be able to recover fordamagetothecotton);Louisville&NashvilleR.R.Co.v.Joullian,76So.769(Miss.1917).

52SeeRobert C. Ellickson, OfCoaseandCattle:DisputeResolutionAmongNeighbors inShastaCounty,38Stan.L.Rev.623,665‐66(1986)(surveyingcasestothateffect).Ellicksonalsonotes,however,that“evenrancherswhoknowthattheyarelegallyentitledtorecoverfeedingcostsvirtuallyneverseekmonetarycompensationforboardingestrays.”Id.at674.

53“The term ‘estrays’ at common law had thewell‐definedmeaning of animals foundwanderingat large,whoseownershipwasunknown.”Yraceburnv.Cape,212P.938,940(Cal. 1st Dist. Ct. App. 1923). For a modern, statutory definition, see CAL.AGRIC.CODE §17001.5(West,WestlawthroughCh.309of2013Reg.Sess.)(“Forpurposesofthischapter,‘estray’meansanyimpoundedorseizedbovineanimal,horse,mule,sheep,swine,orburrowhoseownerisunknownorcannotbelocated.”).

54See,e.g.,CAL.AGRIC.CODE§17041(West,WestlawthroughCh.309of2013Reg.Sess.).


17

damage feasant or distress damage feasant.55Despite this privilege of self‐help, the

landowner is generally not privileged to wound or kill the trespassing animals.56As

elsewhereintortlaw,alltheseprinciplesaresubjecttoareasonablenessstandard.

2. TrespassbyRobots

Theanimalcasesposeinterestingpossibilitiesforinstancesofrobottrespass.Some

scholarsequatethemoralclaimsofautonomousrobotswiththoseofanimalsandothers

55See Kelly v. Easton, 207 P. 129 (Idaho 1922) (“This right [to seize and detaintrespassing animals] existed at common law andwas not introduced by statute, but thematter is now regulated by statutory enactments in the several states, providing for theseizure and impounding of cattle taken damage feasant, and for their sale.”) (internalcitationomitted).Distress,generally,wasdefinedatcommonlawas,

the taking, either with legal process, or extra‐judicially subject to theperformanceofsomenecessaryconditionprecedent,byaprivateindividualorbyanofficerofthecourt,ofapersonalchattel,outofthepossessionofawrongdoerordefaulterandintothecustodyofthelawtobeimpoundedasapledge inorder tobringpressure tobearupon theownerof the chattel toredressan injury, toperformaduty,or tosatisfya lawfuldemand,subject,however,totherightoftheownertohavethechattelreturnedtohim[up]ontheinjurybeingredressed,orthedutyperformed,orthedemandsatisfiedor[up]onsecuritybeinggivensotodo.

F.A.ENEVER,HISTORYOFTHELAWOFDISTRESSFORRENTANDDAMAGEFEASANT7–8(1931). TherightofdistressdamagefeasantisdescribedbyBlackstoneasfollows:

A man is answerable for not only his own trespass, but that of hiscattle also; for, if by his negligent keeping they stray upon the land ofanother, (andmuchmore if he permits or drives themon,) and they theretreaddownhisneighbor’sherbageand spoil his cornorhis trees, this is atrespassforwhichtheownermustanswerindamages,andthelawgivesthepartyinjuredadoubleremedyinthiscase,bypermittinghimtodistrainthecattle thusdamage‐feasant,ordoingdamage, till theownershallmakehimsatisfaction,orelsebyleavinghimtothecommonremedyinforocontentioso,byaction.

3WILLIAMBLACKSTONE,COMMENTARIESONTHELAWSOFENGLAND*211;seealsoHallv.Marshall,27 P.2d 193, 195 (Or. 1933) (quoting Blackstone’s description with approval); Kelly v.Easton,207P.129,130(Idaho1922)(same).

56SeeRobert C. Ellickson, OfCoaseandCattle:DisputeResolutionAmongNeighbors inShasta County, 38 Stan. L. Rev. 623, 666 (1986) (surveying cases to that effect); M.L.Schellenger, Civil Liability of a Landowner for Killing or Injuring Trespassing Dog, 15A.L.R.2d578(1951).


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suggest that animal law provides a useful model for robot law.57 Though animals are

technicallychattels,theanimalcasesshowagreatersolicitudeforlife,non‐humanthough

itmaybe.58Werecourts todecide that robotsaremore likeanimals thanrobotsare like

inanimatechattels,thentheprivilegetouseviolentself‐helpmeasureswouldbenarrower.

Untilthatday,however,thelawwilltreatrobotsaschattels.Theself‐helprightsofpersons

whoareorbelievethemselvestobethreatenedbyrobotswillbeanalyzedunderthetort

rulesdevelopedforself‐helpagainsttortscommittedbyorwithchattels.59

Inprinciple, victimsof actionable trespasshaveaprivilegeof self‐help.60Self‐help

rangesfromstoppingtheinvader61todamagingorevendestroyingit62ifthereappearsto

benootherwaytostopit. Iftheroboticinvaderisanairbornedrone,thisprivilegemay

extendtoshootingitdown.63In2013theCongressionalResearchServicefound“nocases

wherea landownerwaspermittedtouseforcetopreventorremoveanaircraft fromhis

property.”64Butthatiswhatonewouldexpectinaworldwhereaircraftaremanned—no

57Seee.g.,Kate Darling,ExtendingLegalRightstoSocialRobots,We Robot Conference,UniversityofMiami,April2012,availableathttp://ssrn.com/abstract=2044797;F.PatrickHubbard, “DoAndroidsDream?”:PersonhoodandIntelligentArtifacts, 83TEMP.L.REV. 405(2011);MarkCoeckelbergh,RobotRights?TowardsaSocial‐RelationalJustificationofMoralConsideration, ETHICS AND INFORMATION TECHNOLOGY, Sept. 2010, at 209, available athttp://link.springer.com/article/10.1007/s10676‐010‐9235‐5.

58See,e.g.,Bruisterv.Haney,102So.2d806(Miss.1958)(upholdingpunitive‐damageaward against trespass victimwho poisoned trespassing cattle); Strong v. Georgia Ry.&Elec.Co.,45S.E.366(Ga.1903)(eulogizingdeceaseddog).

59Thedistraintremedyisnotlimitedtotheanimalcontext,seeSearsv.Summit,Inc.,616P.2d765(Wyo.1980)(recognizingprivilege toseizeconstructionequipment thatcausesdamage,butfindingitexceededonfactsofcasebecauseequipmentcausedlittledamage).

60RESTATEMENT(SECOND)OFTORTS§260(1965).61E.g., Rossi v. Ventresca Bros. Const. Co., 405N.Y.S.2d 375 (City Ct. 1978) (stopping

trespassbycarbytowingit).62E.g., Forster v. JuniataBridgeCo., 16Pa. 393 (1851) (holding thatwhile landowner

wasnotjustifiedinappropriatingbridgecastontohislandbystorm,hewouldhavebeenprivilegedtocastthebridgebackintotheriver).

63Shooting down a dronewith a projectile is not the onlyway to disable a drone orengageinself‐helpagainstone:onemightalsouseajammer,oranEMP,orsimplycastanetoverthedrone.Thispaperfocusesonthepermissibilityoffiringaprojectiveatadronebecause if shootingdownadrone ispermissibleunderanygivenset circumstances thenotherlessdangerousmeansalsowillbepermissibleinthosesamecircumstances.

64ALISSAM.DOLAN&RICHARDM.THOMPSONII,CONG.RESEARCHSERV.,R42940,INTEGRATIONOFDRONESINTODOMESTICAIRSPACE:SELECTEDLEGALISSUES29(2013).


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oneshouldbeabletoriska lifetoprotectproperty.65Anunmanneddronewillnotenjoy

thisblanketlegalprotection.66

Inadditiontodestroyingtheroboticinvaderbysomemeans,somesortofdistraint

remedy,67i.e. capture and security, may also be available where the damages done, or

reasonablybelievedtohavebeendone,appeartoatleastequalthevalueofthetrespassing

robot.Inthecaseofanairbornedrone,eveniftheinfringementofairspacedidnotalone

justify the distraint remedy, the drone may cause property damage after being forced

down; that additional harm is also charged to the tortfeasor’s account because it is a

reasonably foreseeable consequence of the trespass.68If the robot appears substantially

morevaluablethanthenominaldamageithasdone,thevictimofthetrespasslikelycannot

holdtherobot.69

Weighingagainsttherighttoshootdownadronearetherisksanyshootingorother

attempttojamordisableanairbornevehicleentails.Therisksoffiringagunintotheair

areobvious,asaretherisksofcausingadrone—whichmayberatherlarge—tofalloutof

thesky.70Tortlaw’subiquitousreasonablenessstandardwoulddemandthataself‐helper

65See,e.g.,Andersonv.Smith,7Ill.App.354,358(Ill.2dDist.Ct.App.1880)(notingthatbecause the lawplaces “sucha transcendentvalueuponhuman life . . . [,] it conclusivelypresumesthat it isnotreasonableto takethe lifeofahumanbeingwhenthethreatenedinjury,ifconsummated,wouldbebutameretrespassormisdemeanor.”);seegenerallyW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS133‐34(5thed.1984)(“Eventhetraditionthataman’shouseishiscastle,andthatonemaykillindefenseofhisdwelling,hasgivenway inmost jurisdictions to theview that such force isnot justifiedunless the intrusionthreatens thepersonal safety of the occupants.”) (footnotes omitted);RichardA. Posner,KillingorWoundingtoProtectaPropertyInterest,14J.L.&ECON.201(1971).

66Seesupratextaccompanyingnote40.67Seesupranote54.68Thegeneralprincipleisthatonceapartycommitsaninitialtort(here,thetrespass),

thatparty isalso liable foralldamagesproximatecausedby thatharm–often includingmanydamagessufferedby(andevenreasonableonescausedby)thoserespondingtotheinitialtrespass.SeeRestatement(Second)ofTorts§435A(1965)(“Apersonwhocommitsatortagainstanotherforthepurposeofcausingaparticularharmtotheotherisliableforsuchharmifitresults,whetherornotitisexpectable,exceptwheretheharmresultsfromanoutsideforcetheriskofwhichisnotincreasedbythedefendant'sact.”).Here,theinitialtrespasswouldhaveincreasedtheriskofoutsideharmintheformofreactiveself‐help.

69Seesupratextaccompanyingnote42.70See, e.g., J. David Goodman, Remote‐Controlled Model Helicopter Fatally Strikes Its

Operator at a Brooklyn Park, N.Y. TIMES, A19, (Sept. 6, 2013), available at


20

recognizetheseforeseeablerisksandaccountfortheminhercost‐benefitanalysisbefore

allowingaself‐defenseprivilege.71Thecalculuswillthusbeverydifferentonanopentract

ofland,wherethereisnooneelsetohurt,thanitwouldbeinacrowdedcommunity.

Determining the scope of permissible self‐help will always complicated by the

difficulty victimswill have in trying to ascertainwhat the invading robot is doing. That

difficultyisparticularlyacutewhentherobotisairborne,foritwillbehardertoexamine

duetodistance,speed,and(atnight)lightingconditions.Atleastsolongasdronesarean

experimentaltechnology,thisuncertaintylikelywillbefoundtojustifymoreself‐help.As

drones become more common, and presuming it becomes routine to see them being

operatedinasafemanner,thecalculuslikelywillshift.Intheshortterm,however,wemay

seecourts inruralareasfindingaprivilegetoshootdownatrespassingdronebecauseit

will rarely if ever be clear that a drone's overflight is no more than a purely technical

trespass: if nothing else the drone’s very existence in the airspace above persons and

propertyposesatheoreticalthreatofacrash.72Theymightbearmed.Asdiscussedfurther

http://www.nytimes.com/2013/09/06/nyregion/remote‐controlled‐copter‐fatally‐strikes‐pilot‐at‐park.html?smid=pl‐share&_r=1&; Joe Sutton, 2 Injured When DroneMalfunctions, Crashes Into Navy Ship, CNN U.S., (November 17, 2013, 10:37 AM),http://www.cnn.com/2013/11/17/us/drone‐malfunction‐duplicate‐2/.

71The implications of this rule canbe seen from the following example: Homeownershootsadroneinapopulatedarea.Homeownerisagoodshotandhitthedroneandnooneis injured when it crashes. Homeowner’s action was unreasonable but it ended well.Nevertheless, Homeowner’s action was not privileged because there never existed aprivilegeofself‐helpasareasonablepersonwouldnothavetakentheshot.Anyotherrulewould reward and thus encourage attempts at unreasonable self‐help even when itthreatenedpublicsafety.

72See, e.g., Joe Sutton, Two InjuredWhenDroneMalfunctions,Crashes IntoNavy Ship,CNN, (Sept. 17, 2013), available at http://www.cnn.com/2013/11/17/us/drone‐malfunction‐duplicate‐2/index.html; J. David Goodman, Remote‐Controlled HelicopterFatally Strikes its Operator, N.Y. TIMES (Sept. 5, 2013), available athttp://www.nytimes.com/2013/09/06/nyregion/remote‐controlled‐copter‐fatally‐strikes‐pilot‐at‐park.html. A somewhat similar caseof ever‐present riskof greater‐than‐nominalharmappliesinanimalcases.RobertC.Ellicksonnotesthat“[b]ecausecattleeatalmostincessantly,atrespassvictim’svegetationisalwaysatrisk.”RobertC.Ellickson,OfCoaseandCattle:DisputeResolutionAmongNeighborsinShastaCounty,38STAN.L.REV.623,658(1986).Further,trespassbyanon‐thoroughbredbullintothevicinityofthoroughbredfemalecattle,whilemerelyatechnicaltrespassintheabsenceofactualdamages,posesthemoreseriousriskofimpregnationandproductionofoffspringofanundesiredpedigree.Id.


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below,bothairandgroundrobotsalsomightspy.Atleastuntilsomestandardstakeshape,

the victim of a trespass may be entitled to assume the worst, i.e., that the robot is not

merely trespassing but is recording. If one is entitled to assume theworst then, in the

absence of persuasive notice that the robot is harmless, the victim of robotic trespass

frequentlywillbeprivilegedtoemployviolentself‐help.73

Beforelandownersstartreachingfortheirshotguns,however,theyshouldbeaware

thatcurrenttrespasslawcreatesatleasttwosubstantialobstaclesforlandownersseeking

legal justification forself‐helpagainstoverflyingdrones. The first,andmoresubstantial,

difficulty lies in charting the boundaries of private airspace—the space over which a

landownercanclaimtheabsolutepossessoryrightthatisaperquisitetoatrespassclaim;

thisturnsouttobeacomplexissueinvolvingbothstateandfederallaw.Landownerswill

needtoknowhowfederalandstatelawinteracttoshapetheirairrights,andhowthoseair

rightsaffecttheirprivilegeofself‐help.

Asecondissueisthat inpracticesomecourtsareunfriendlytoclaimsoftechnical

trespassandtendtorequireactualharmbeforeallowinganaerialtrespassclaim.Inthese

jurisdictions, it may be fair to ask if technical trespass actions exist at all, or whether

instead the courts have in practice converted them into nuisance claims,which unlike a

trespassclaim,requiresactualharm.74

a. DefiningPrivateAirspace

The starting point for determining what constitutes an aerial trespass is

determining theextentof theairspace coveredbya landowner’s right toexcludeothers.

Theancientrulegavealandownerrightsallthewaytothemoon,75butthatrulehaslong

beenabrogatedtoallowmodernairtravel.76Yetalandownerstillhasexclusiverightsto

Theprivilegetodefendone’sthoroughbredstockinsuchasituationatleastoncesuppliedan affirmative defense to the criminal charge of malicious mischief. See Hummel v.Oklahoma,99P.2d913(Okla.Crim.App.1940).

73Seesupratextaccompanyingnotes59‐65.74Seeinfra§II.C.2.b.75Thiswasthedoctrineofadcoelumunderwhichalandowner’sownershipextendedto

“theperipheryoftheuniverse,”uptotheheavensanddowntothedepths.SeeUnitedStatesv.Causby,328U.S.256,260‐61(1946).

76SeeUnited States v.Causby, 328 U.S. 256 (1946) (holding that “the air is a publichighway”);seealsoTimothyM.Ravich,TheIntegrationofUnmannedAerialVehiclesIntothe


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someof theairspaceoverher land. It followsthat landownersshouldbeable toclaima

freedomfromdroneoverflightinatleastsomeportionoftheirairspace.Thequestionsare

howhigh,andwhosetstheboundaries.

Althoughinprinciple“invasions[ofairspace]areinthesamecategoryasinvasions

of the surface,”77today’s landowners do not have an absolute possessory right to all the

airspace above their land,whether their claims arebasedon theTakingsClause,78or on

tortandcontractprinciples.79 Instead,a landownerhas theright toonly“asmuchspace

above the ground as he can occupy or use in connection with the land.”80That the

landowner has not in fact used the airspace is not material; the land must only be

reasonably subject to use.81 Unhelpfully, the SecondRestatement states that “[f]light by

aircraftintheairspaceabovethelandofanotherisatrespassif,butonlyif, . . . itenters

intotheimmediatereachesoftheairspacenexttotheland.”82

Common‐lawrulesdefiningalandowner’sairspacecanbepreemptedbystatute.83

Congresshasdeclareda“publicrightoffreedomoftransitthroughthenavigableairspace”

NationalAirspace, 85N.D.L.REV.597,604‐05 (2009) (discussinghistoryofadcoelumanditsabandonmentduringtheeraofmassairtransit).

77328U.S.at265.78328U.S.at256.79See,e.g.,Brandesv.Mitterling,196P.2d464(Ariz.1948); Jonesv.Wagner,624A.2d

166(Pa.SuperiorCt.1993)(dealingwithtrespassbyoverhangingtreebranches);seealsoALISSA M. DOLAN & RICHARD M. THOMPSON II, CONG. RESEARCH SERV., R42940, INTEGRATION OFDRONES INTO DOMESTIC AIRSPACE: SELECTED LEGAL ISSUES 11 (2013) (stating that Causbystandards “areused inproperty tortclaimsbecause therecanbeno trespass inairspaceunlessthepropertyownerhassomepossessoryrighttotheairspace,whichwasthesamequestionatissueinCausby.”).

80328U.S.at264.81328U.S.at264.82RESTATEMENT(SECOND)OFTORTS§159(2)(a)(1965)(emphasisadded).83NotethattheSupremeCourt’scasesaddressingaerialsurveillanceundertheFourth

Amendment do not decide the issue of private air rights because the warrantlessobservationswerealltakenfromwithintheFAA‐definednationalairspace.SeeCaliforniav.Ciraolo,476U.S.207(1986)(allowingwarrantlessaerialobservationoffenced‐inbackyardwithincurtilagefromaltitudeof1,000feet);DowChemicalCo.v.UnitedStates,476U.S.227(1986) (warrantless aerial surveillance of chemical plant from within “lawful navigableairspace” of 1,200 feet and higher); Florida v.Riley, 488 U.S. 445 (1989) (warrantlesssurveillancefromhelicopterflyingat400feet).Theissueinthesethreecaseswaswhetherthesurveillancewasa“search”withinthemeaningoftheFourthAmendmentsuchthata


23

oftheUnitedStates.84“Navigableairspace”isdefinedastheairspaceabovetheminimum

safe operating altitudes, including airspace needed for safe takeoff and landing.85FAA

regulationsdefinetheseminimumsafe‐operatingaltitudesfordifferentkindsofaircraft.

Generally,apartfromtakeoffandlanding,fixed‐wingaircraftmustbeoperatedatan

altitudethatallowstheaircrafttoconductanemergencylanding“withoutunduehazardto

personsorpropertyonthesurface.”86Inacongestedarea,theaircraftmustoperateatleast

“1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet on the

aircraft.”87Inanon‐congestedarea,theminimumsafe‐operatingaltitudeis“500feetabove

thesurface.”88Overopenwaterorsparselypopulatedareas,aircraft“maynotbeoperated

closerthan500feettoanyperson,vessel,vehicle,orstructure.”89

Unlike fixed‐wing aircraft, which are subject to specific minimum safe‐operating

altitudes based on location, regulation of helicopterminimum altitudes ismore flexible.

UnderFAARegulations,ahelicoptermayflybelowtheminimumsafealtitudesprescribed

for fixed‐wing aircraft if it is operated “without hazard to person or property on the

surface.”90

TheFAAdoesnotcurrentlyregulateminimumsafe‐operatingaltitudesfordrones.91

InitsupcomingregulationstheFAAmightcreatedifferentclassesofrulesfordronesbased

warrant was required. These cases do not address the extent of the National AirspaceSystem;rathertheyaddresswhatalaw‐enforcementofficermaydowhenwithinit.

8449U.S.C.§40101(c)(2)(2012).8549U.S.C.§40102(a)(32)(2012).8614C.F.R.§91.119(a)(2010).87Id.at§91.119(b).88Id.at§91.119(c).89Id.90Id.at§91.119(d).91See ALISSA M. DOLAN & RICHARD M. THOMPSON II, CONG. RESEARCH SERV., R42940,

INTEGRATIONOFDRONESINTODOMESTICAIRSPACE:SELECTEDLEGALISSUES3(2013).ButwhiletheFAA does not currently regulateminimum safe operating altitudes for drones, it did, in2007, issue a policy notice stating that “no person may operate a UAS in the NationalAirspace without specific authority.” Unmanned Aircraft Operations in the NationalAirspaceSystem,72Fed.Reg.6689 (Feb.13,2007).Thismeans thatalldroneoperatorswho do not fall within the recreational‐use exemption, id., must apply to the FAA forpermission to fly. For recreational users of model aircraft—a classification that couldincludecertaintypesofdrones,seeHuertav.Pirker,DocketNo.CP‐217(FAAMar.6,2014)(holdingthatFAAdidnothaveauthoritytoregulatemodelaircraft,thusassumingthatthe


24

ontheirsizeandcapabilities.Largerdronesresemblingfixed‐wingaircraftcouldbesubject

to altitude requirements similar to manned aircraft, whereas smaller drones might be

regulated likehelicoptersormightenjoyasuigeneris rule. However theFAAsets these

standards,once inplace theywill set the lowerbounds forwheredronesmaybe legally

overfly private property. If federal law defines a portion of the airspace as publicly

navigable, thatmeansdroneoperatorsaresafe fromanactionforsimpletrespasswithin

that zone. The lack of a cause of actionwould in turn preclude any self‐help privilege.

However, an action for nuisance or invasion of privacy would still be possible.92

Furthermore, since the FAA may not regulate recreational use of model aircraft,93a

classificationthatcouldincludecertaintypesofdrones,94statepropertylawwillcontinue

toplayaroleindefiningtheboundsofprivateairspacerelevanttouseofflyingrobots,and

statetortlawwillcontinuetodefinehowlandownersmayreacttotrespassoryoverflights

byhobbypilots.

aircraftatissuewasinfactahobbyaircraftasopposedtoacommercialdroneastheFAAhad alleged)—the FAA currently encourages compliance with a 1981 advisory circular.UnmannedAircraftOperationsintheNationalAirspaceSystem,72Fed.Reg.6689(Feb.13,2007).Compliancewiththecircular isvoluntary,AdvisoryCircular91‐57,ModelAircraftOperating Standards (June 9, 1981), available athttp://www.faa.gov/documentLibrary/media/Advisory_Circular/91‐57.pdf., but it makesthefollowingsuggestions.Usersareurgedtoflyasufficientdistancefrompopulatedareasand away fromnoise‐sensitive areas likeparks, schools, hospitals, or churches. Id.Usersshouldnotflyinthevicinityoffull‐scaleaircraftormorethan400feetabovethesurface.Id.Whenflyingwithinthreemilesofanairport,usersshouldnotifyanairportofficial.Id.

92See Thornburg v. Port of Portland, 376P.2d 100, 108 (Ore. 1962) (noting that jurycould find noise nuisance in spite of fact that airplaneswerewithin navigable airspace:“[t]here is no merit in the defense that all flights within the navigable airspace areautomatically free from liability”); Nader v. General Motors Corp., 255 N.E.2d 765, 768,770‐71(recognizingthatthetortofinvasionofprivacydoesnotrequireaphysicaltrespassonplaintiff’spropertybutcouldbeaccomplishedbyremotelyeavesdropping).

93FAAModernizationandReformActof2012,Pub.L.No.112‐95at§336(a),126Stat.11,77.

94SeeHuertav.Pirker,DocketNo.CP‐217(FAAMar.6,2014)(holdingthatFAAdidnothave authority to regulate model aircraft, thus assuming without discussion that theaircraftatissuewasinfactahobbyaircraftasopposedtoacommercialdroneastheFAAhad alleged). The FAA is appealing this decision. SeeFAA Press Release, (Mar. 7, 2014),http://www.faa.gov/news/press_releases/news_story.cfm?newsId=15894.


25

In thezonebelowthatcoveredby federal laworregulation, justhowclose to the

ground constitutes the “immediate reaches”95protected from intruders may vary from

statetostate.96StatescansettheboundarybelowtheFAAstandards.Thatis,whileastate

may not prohibit overflights that the FAA permits, the state may expand the navigable

airspaceattheexpenseofthepropertyowner’sexclusiveairspacebysettingthetrespass

linelowerthantheFAA’sminimumaltitude.97

Anextremeversionofhowstateandlocallawmightaddressthesegapsinfederal

regulationcanbefoundin DeerTrail,Colorado. ThetownofDeerTrail isconsideringa

plan to offer its residents drone‐hunting licenses.98The FAA, however, has expressed

skepticismat the legalityof shootingdowndrones. In response toDeerTrail,Colorado’s

plan,theFAAstatedthat“Shootingatanunmannedaircraftcouldresultincriminalorcivil

liability, just aswould firing at amanned airplane.”99However, the FAAdidnot cite any

95Seesupratextatnote81.96SeeRESTATEMENT(SECOND)OFTORTS § 159 cmt. l (1965) (“‘Immediate reaches’ of the

land has not been defined as yet, except to mean that the aircraft flights were at suchaltitudes as to interfere substantially with the landowner's possession and use of theairspaceabove the surface.Nomoredefinite line canbedrawn than is suggestedby theword‘immediate.’Intheordinarycase,flightat500feetormoreabovethesurfaceisnotwithinthe‘immediatereaches,’whileflightwithin50feet,whichinterfereswithactualuse,clearly is, and flightwithin 150 feet,which also so interferes,maypresent a question offact.”) (internal quotationmarks omitted); Bevers v. GaylordBroadcasting Co., 2002WL1582286,*6(Tx.Ct.App.2002)(decliningtospecificallydefine“immediatereaches,”butholdingthat“asingleten‐minutehoverover[thelandowner’s]propertyat300to400feetdoes not, as a matter of law, rise to the level of ‘substantial interference’”) (footnoteomitted);ActofJul.29,2013,ch.686,2013Or.Laws686§15(2013)(providingtrespasscause of action for drone overflight below 400 feet if (1) there has been a previousoverflightbelow400feet(2)afterwhichthelandowner“notifiedtheowneroroperatorofthedronethatthe[landowner]didnotwantthedroneflownoverthepropertyataheightoflessthan400feet”),

97Seee.g.,ActofJul.29,2013,ch.686,2013Or.Laws686§15(settingminimumheightfordroneoverflightat400feet,wellbelowFAAminimumheightoverflightlimitsforfixed‐wingaircraft).

98AnaCabrera,Coloradotown’svoteondroneordinancepostponed, CNNU.S., (accessed1/26/14 11:44 AM) http://www.cnn.com/2013/12/10/us/colorado‐town‐drone‐ordinance/.

99Id.(quotinguncitedFAApressrelease).


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specificlawbackingthisassertionandtheauthorityforitisdependsuponhowonereads

thestatutegoverningdestructionofaircraft.100

b. Whether to Require Actual Harm: Conflation with the Tort of

Nuisance

While trespass is generally subject to a rule of strict liability,101in cases of aerial

trespasstherulemergeswiththetraditionalstandardfornuisance,whichrequiresactual

damages.102TheRestatement(Second)ofTortsnotes inacomment that it isa trespass to

“fire projectiles or to fly an advertising kite or balloon through the air above [another’s

land],eventhoughnoharmisdonetothelandorthepossessor’senjoymentofit.”103This

reflects the normal strict‐liability rule. But in the very next section, the Restatement

declaresthat,“[f]lightsbyaircraftintheairspaceabovethelandofanotherisatrespassif,

100See 18 U.S.C. § 32(a)(1) (2012). The issue is whether 18 U.S.C. § 32(a)(1) coversshootingdownadroneorwhether that statute isbestunderstood to apply solely to thedestruction of manned aircraft. Section 32(a)(1) makes it a crime punishable by up totwentyyearsinprisontowillfullydestroy“anyaircraftinthespecialaircraftjurisdictionoftheUnitedStatesoranycivilaircraftused,operated,oremployedin[commercesubjecttofederalregulation].”18U.S.C.§32(a)(1)(2012).An“aircraft”isdefinedas“acivil,military,orpubliccontrivance invented,used,ordesignedtonavigate, fly,or travel in theair.”18U.S.C. § 31(a)(1) (2012). Read broadly, § 32(a)(1) would seem to apply even to thedestructionofamodelhelicopterandcertainlywouldcoverroboticaircraft.While§32(a)(1)makes itacrimetodestroyan“aircraft,”18U.S.C.§32(a)(1)(2012),

othersubsectionsof§32referinsteadtoan“aircraftinflight.”See,e.g,18U.S.C.32(a)(3),(7)(2012).Thedefinitionof“inflight”assumesthattherehasbeen“embarkation”andwillbe“disembarkation,”see18U.S.C.§31(a)(4),twotermsthatgenerallyrefertopassengers.The different language in § 32(a)(1) provides a textual hook for the argument thatCongress intended to extend coverage to the destruction of unmanned aircraft. On theother hand, one could easily ask whether Congress intended such a potentially absurdresult. At the time of the passage of the 1956 Act to Punish the Willful Damaging orDestroyingofAircraftorMotorVehicles,andTheirFacilities,andforOtherPurposes,Pub.L.No.709,70Stat.539,thestatuteenactingwhatbecamecodifiedas§32(a)(1),itseemshighlyunlikelythatCongressintendedtoimposeatwenty‐yearsentencefordestructionofamodelairplaneorthatthatCongressforesawtheintroductionofroboticaircraft.

101RESTATEMENT(SECOND)OFTORTS§158(1965).102SeeColinCahoon,LowAltitudeAirspace:APropertyRightsNo‐Man'sLand,56J.AirL.

&Com.157,175‐76(1990)(notingthatcommentators“haveacceptedthisunconventionalapproachasuniquetoairspacetrespassanalysis”).

103RESTATEMENT(SECOND)OFTORTS§158cmt.i(1965).


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butonlyif,...itinterferessubstantiallywiththeother’suseandenjoymentoftheland.”104

This rule superimposes a requirement of actual harm, thus conflating the normal strict‐

liabilityruleoftrespasswiththeruleofnuisance.105

Generally,aprivate106nuisance isa “nontrespassory invasionofanother’s interest

in the private use and enjoyment of land.”107Whereas a trespass is inherentlywrongful,

104RESTATEMENT(SECOND)OFTORTS§159(1965).105By importing requirements fromanuisanceclaim thisdeparture fromthe trespass

ruleeffectivelyswallowstheaerialtrespassaction.Thecourts’detourintoaerialnuisancemay be based on a misreading of the United States Supreme Court’s decision inUnitedStates.v.Causby,328U.S. 256 (1946) (holding that “frequent and regular flightsof armyand navy aircraft over respondents' land at low altitudes” below those “within thenavigable airspace which Congress placed within the public domain” sufficientlydiminishedvalueofpropertytoallowTakingsclaimundertheFifthAmendment).CourtshavereadCausbytorequireactualinterferencewiththeowner’suseorenjoymentofherlandfortheoverflighttobeanactionabletrespass.See,e.g.,PuebloofSandiaexrel.Chavesv.Smith,497F.2d1043,1045‐46(10thCir.1974)(affirminggrantofsummaryjudgmentinfavorofdefendantwhereplaintiffintrespassactionfailedtoallegeinterferencewithactualuse);seealsoRESTATEMENT(SECOND)OFTORTS§159cmt.k(1965)(notingthatfederalcaseshave read Causby this way in the trespass context).This reading seems anomalous: inCausby theSupremeCourtheldthat for theretobea takingundertheFifthAmendment,that is, for the government to have appropriated private property under circumstanceswhich require payment of compensation, see U.S. CONST. amend. V, there must besubstantialinterferencewiththeowner’suseorenjoyment.328U.S.at266(“Flightsoverprivatelandarenotataking,unlesstheyaresolowandsofrequentastobeadirectandimmediate interference with the enjoyment and use of the land.”). There is no obviousreasonwhy the interferencerequirement shouldbeas strict ina trespassclaim. If aerialtrespassgenuinelyistobetreatedliketerrestrialtrespass,thenallthatshouldberequiredisentranceintothatpartoftheairspacethatremainsfullyprivate.Causbyexpresslyholdsthat a landowner’s nonuse of airspace does not affect ownership. 328 U.S. at 264 (“Thelandownerownsatleastasmuchofthespaceabovethegroundashecanoccupyoruseinconnectionwith the land.The fact thathedoesnotoccupy it inaphysicalsense—bytheerection of buildings and the like—is not material.”) (citation omitted). Properlyunderstood, then,Causbymakesactual interferencewithuserelevantonlyasamatterofsubstantiveConstitutionalTakings law,not as amatterofproperty lawonownershipofairspace. If,however,statecourtscontinuetoimportCausbyintoaerialtrespasslaw,theeffectwillbetominimizetheimportanceoftrespassasapotentialjustificationforself‐helpagainst aerial intrusions and thus increase thepotential importanceof nuisancebecausetherewillbecasesofclassic trespass thatdonotamount tonuisance ifonlybecause theinterferencewasneitherrepeatednorcontinuous.

106This is as compared with a public nuisance. SeeRESTATEMENT (SECOND) OFTORTS §821B(1965).Aprivatenuisanceinterfereswithanindividual’suseandenjoymentofherland,whileapublicnuisanceinterfereswith“arightcommontothegeneralpublic.”Id.


28

conduct constituting a nuisance is not. The conduct constituting the nuisance becomes

wrongfulonlywhenitinterfereswiththeplaintiff’suseandenjoymentofherland.108

Nuisancelawusuallyrequirestheinterferencetoberepeatedorongoingbeforeit

becomes actionable.109A one‐time interferencemay be enoughwhere it causes ongoing

harm, but otherwise a single instance of nuisance‐like activitywould not ordinarily give

rise toanuisancecauseofaction: thequestion iswhether the interference is substantial

andunreasonable.Thetypesofproblemsthatdronesarelikelytocause—noise,110dust,111

lowoverflights112—wouldordinarily requiremultiple instancesof inappropriate conduct

byasinglepartybeforecreatingarighttosueandthusarighttoself‐help.

Onemightreasonablyaskhowthepropertyownerissupposedtoknowwhoowns

the drones overflying her property. In theory, however, in a nuisance‐only regime the

lucklessdroneoperatorwhoforthefirsttimeflewadroneoverapropertythathadbeen

overflownmany timesbyotherswouldhave a causeof actionagainst a propertyowner

whodamagedthedrone.Inapuretrespassregime,bycontrast,thepropertyownerwould

havetheclaimsolongasshehadanexclusiverighttotheairspaceandherself‐helpwas

otherwisereasonable.

D. InvasionofPrivacybyRobotsasaJustificationforSelf‐Help

Privacy torts present the most difficult but also some of the most important

justificationsforself‐defenseagainstrobots. Invasionsofprivacycanbeverysignificant

107RESTATEMENT(SECOND)OFTORTS§821D(1965).108SeeW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS623(5thed.1984).109Thereisnoactualrequirementofcontinualinterference;therequirementisonlythat

theinterferencebesubstantialandunreasonable,arequirementthatoftencannotbemetabsent repeatedoffenses.SeegenerallyW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS626‐30(5thed.1984).

110SeeNestle v. City of SantaMonica, 496 P.2d 480 (Cal. 1972) (denying recovery oninverse‐condemnation claim predicated on airplane noise interference, but reversingdismissal of nuisance claim); Thornburg v. Port of Portland, 376 P.2d 100 (Or. 1962)(notingthatitisaquestionforthejuryastowhethertherewasatakingbynoisenuisance).

111SeeDayton v. City of Asheville, 115 S.E. 911 (N.C. 1932) (holding that odors, dust,smokeandratsfromasewerplantconstitutedanuisance).

112SeeSealev.Pearson,736So.2d1108(Ala.App.1999)(affirmingtrialcourt’sfindingofnuisancebasedonlowoverflights).


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harms, so the privilege of self‐help should in theory be broad.113 That said, there are

significant issueswithhowapersonfacingarobotcouldknowwhat it iscapableof,and

(justas in thecaseof trespass114) theextent towhichaperson isentitled toassume the

worst.Whetherornotonecanassumetheworstoftherobot,therearealsodifficultissues

ofdecidingwhenapotentialharmjustifiesthefinancialcostofharmingtherobot.

Thiscost‐benefitanalysisisparticularlydifficultforprivacytortsbecauseitinvolves

value judgments about privacy, requiring us to ask what sorts of self‐help should be

permitted,ratherthanjustwhetherthedronelooksmoreexpensivethanthepropertyto

bedefended.It iseasytosaythatonemaynotdestroyathingofgreatvaluetoprotecta

thingoflittlevalue,butitisclearlydifficulttoextendthisprecisecalculustoareaswhere

theinterestinpropertyistobebalancedagainstamoreethereal,oratleastlesseasilyand

immediatelyquantifiable,interestlikeprivacy.

Responsestorobotprivacyinvasionsalsoinvolvequestionsofperceivedthreatsby

robots—perceptions which may not always be justified, but which sometimes may

nonetheless be considered reasonable in law. In addition they include caseswhere the

intrusion is not necessarily detectedwhile it is ongoing. For example, if the landowner

doesnotseeorhearadroneitwillbemuchhardertomakeanuisanceclaimbecauseitis

hardtoarguethatanunnoticedintrusioninterfereswithuseorenjoymentoftheproperty.

Whetherornottheinvasionofprivacyisdetectedwhileitoccurs,theseintrusions

arethedomainofarelativelyexoticbranchoftortlaw,theprivacytorts.Classically,there

are four privacy torts115includingpublic disclosure,116false light,117and appropriation of

nameorlikeness,118buttheonlyonearobotislikelytocommit,andthereforetheonlyone

relevanttothispaper,isintrusiononsolitudeandseclusion.Intrusionuponseclusionisa

113Cf..Hummelv. State,99P.2d913 (Okla.Crim.App.1940) (recognizingprivilege tocastratemongrelbullwhereitthreatenedtoimpregnatethoroughbredcattle);McKeesportSawmill Co. v. Pennsylvania Co., 122 F. 184 (C.C.W.D. Pa. 1903) (stating in dicta thatrailroadmightbejustifiedintakingmoreextrememeasuresthananordinarylandownerbecauseofitspublicdutiesandtheuniqueharmposedbyobstructionsonthetracks).

114Seesupratextaccompanyingnote71.115SeeW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS§117(5thed.1984).116RESTATEMENT(SECOND)OFTORTS§652D(1965).117RESTATEMENT(SECOND)OFTORTS§652E(1965).118RESTATEMENT(SECOND)OFTORTS§652C(1965).


30

recognized,119ifsomewhatunusual,tort,butitsrelativerarityinthecourtsmeansthatitis

poorlychartedlegalterritory.120Thetortofintrusionuponseclusionprotectsanindividual

from(1)“highlyoffensive”intrusionsupon(2)reasonableexpectationsofprivacy.121

Although the core principles of the intrusion‐upon‐seclusion tort arewell defined

andfit therobotcontext, there isuncertaintyas to the interactionof the intrusion‐upon‐

seclusiontortwiththeself‐helpprinciple.Wefoundnocasesholdingthatintrusion‐upon‐

seclusiondoesnotjustifyaprivilegeforself‐helpinappropriatecases.Ontheotherhand,

wehavealsobeenunabletofindanycasesthatsayintrusion‐upon‐seclusiondoescreatea

privilegeforappropriateself‐help.

Thereislikelyasimplereasonwhycaselawgivessolittle—maybezero—guidance

astowhenaprivacytortjustifiesself‐helpbythevictim,andifso,howmuch.Considerone

of the more common types of intrusion upon seclusion cases: the peeping landlord.122

These casesnever seem to involve any legal issue relating to the tenant’s destructionor

conversionofequipmentplacedtospyonherbecausethecircumstanceswouldmakethe

spyinglandlord’scomplaintaboutthetenant’sself‐helpsoimplausible.Supposethetenant

disablesorkeepsthehiddencamerainabedroomorbathroom.Inthesecaseswewould

notexpecttoseeaclaimforreplevinfromthelandlordwhoplacedthecameraasacourt

would see it as pure chutzpah. In Miller v. Brooks,123for example, an estranged wife

trespassedandsecretedacamerainthebedroomofherhusband’sapartment,prompting

119See RESTATEMENT (SECOND) OF TORTS § 652B (1965); ALISSA M. DOLAN & RICHARD M.THOMPSON II, CONG.RESEARCH SERV.,R42940, INTEGRATIONOFDRONES INTODOMESTICAIRSPACE:SELECTEDLEGALISSUES14n.111(2013)(“NorthDakotaandWyomingaretheonlystatesnottoadopttheprivacytortofintrusionuponseclusion.”).

120For general discussion see, e.g.,W.PAGEKEETON,ETAL.,PROSSERANDKEETONONTORTS854‐56(5thed.1984);Mitchel J.Ezer,IntrusiononSolitude:HereinofCivilRightsandCivilWrongs,21LawinTransition63(1961);DanielJ.Solove,ATaxonomyofPrivacy,154U.PA.L.REV.477,552‐57(2006).

121RESTATEMENT(SECOND)OFTORTS§652B(1965).122See,e.g.,Roachv.Harper,105S.E.2d564(W.Va.1958);Hambergerv.Eastman,206

A.2d239(N.H.1964).123472S.E.2d350(N.C.Ct.App.1996).


31

thehusbandtotakethecameraandwatchtherecording.Thecourtnotedthisinitssurvey

ofthefacts,124butthewifeapparentlydidnotdemandthecameraorthevideotapeback.

As farasweareaware,claimsofexcessiveself‐help involvingchattelshaveyet to

come up in cases about illegal eavesdropping, wiretapping, or recording. But one can

imaginemanycasesinwhichhomeownersandotherswouldbeconcernedaboutadrone

spying on them and might be motivated to interfere with it or strike at it. A drone

followingsomeonearoundtownlikelywouldbeanactionablenuisanceandinsomecases

mightrisetothelevelofintentionalinflictionofemotionaldistress.125Butwhathappens

whena journalist (orpaparazzi)droneoverfliesapropertywhoseownershoots itdown

fearingthatthedroneisspyingonher?Willthedrone‐owningjournalisthaveaclaimor

willtheself‐helpbeconsideredjustified?

Intheabsenceofguidancefromcaselaw,weturntopolicyargumentsforwhyself‐

helpshouldandshouldnotbeallowedinsuchinstances.

1. Reasons for Permitting Self‐Help Against Robotic Intrusions on

Seclusion

The argument for permitting self‐help in response to the tort of intrusion on

seclusion starts with the two fundamental reasons for permitting self‐help at all.126The

intrusioncreatesanexigency inwhich resort to legallyadministered remedieswouldbe

impractical,asanyrobotequippedwitharadiooracell‐phonechipcantransmitthedatait

records in seconds.Worse, the damage from intrusive recordingsmay be impossible to

remedy after the fact. One cannot purchase new dignity. Second, even violent self‐help

againstanoverflyingdroneposesareducedriskofbreachingthepeacecomparedtothe

ordinaryself‐helpcase.Attackingadroneisnotthesameasattackingitsownerdirectly.127

124Id.at352(notingthathusband“remove[d]thecameraandvideotape”belongingtoestrangedwife).

125See RESTATEMENT (SECOND) OF TORTS § 46(1) (1965) (“One who by extreme andoutrageousconductintentionallyorrecklesslycausessevereemotionaldistresstoanotheris subject to liability for such emotional distress, and if bodily harm to the other resultsfromit,forsuchbodilyharm.”).

126Seesupratextaccompanyingnotes19‐23.127Whereapaparazzoisholdingacamerathelawwillunifythepersonandthechattel

sothattostrikethecameraistostrikethehuman.SeeRESTATEMENT(SECOND)OFTORTS§18cmt.c(1965)(statingthatoffensivebatterycoversnotjustinstancesofdirectcontactwith


32

Plus,thedrone’sowneroroperatoroftenmaynotbeinthenearbyvicinityandthuswill

notbeabletoreactimpulsively—atleastsolongasthedroneitself isunarmed.Society’s

interestinlawandorderthusposesonlyareducedbarriertopermittingevensevereforms

ofself‐helpagainstrobotsindefenseofprivacy.

Twospecificcharacteristicsoftheintrusionuponseclusiontortprovideadditional

justificationsforpermittingself‐help.First,becausethetortrequiresthattheinvasionbe

notjustoffensivebuthighlyoffensive,thenumberofcaseswheretheprivilegeexistswill

dependonhowoffensivesocietyfindsroboticspying.Butinthatsetofrelativelyextreme

cases,howeverlargeorsmall,thescopeofpermissibleself‐helpdeservestobebroad.More

serious threatsandharmsmaybemetwithmorevigorousself‐help.Andwhileaphrase

like “highly offensive” ismalleable, it sets a high bar. In one court’swords, the invasion

mustamountto“outrageouslyunreasonableconduct.”128

Another justification for allowing a self‐help privilege in response to what

reasonablyappearstobearoboticprivacyintrusionisthewaysinwhichprivacyinvasions

by robots differ from privacy invasions by humans. Robots, especially drones, increase

individuals’ ability to spy on others in contexts where the other has a reasonable

expectationofprivacy.Whileneighborsmayhavebinoculars,andaprivatedetectivelikely

has a telephoto lens,129drones are unique in severalways thatmake them potentially a

greaterthreattoprivacy.Theycanspywithouttrespassing.130Wheretheydotrespassthey

theplaintiff,butalsocontactwith“anythingsoconnectedwith[theplaintiff’s]bodyastobecustomarilyregardedaspart [thereof]”).Wherethe landlordplants thecamera inthetenant’sbedroom, theunificationdoesnotoccurbecause there isneither “offense to thedignity involved in the unpermitted and intentional invasion of the inviolability of hisperson” nor “any physical harm done to his body,” and thus the law will not treat thecameraandthelandlordasone.Seeid.

128N.O.C.,Inc.v.Schaefer,484A.2d729,733(N.J.Super.Ct.LawDiv.1984).Forasurveyof cases for which there was and was not liability for intrusion upon seclusion see inRESTATEMENT(SECOND)OFTORTS§652B(1965).

129See,e.g.,RESTATEMENT(SECOND)OFTORTS§652Bcmt.b, illust.2(1965)(“A,aprivatedetective seeking evidence for use in a lawsuit, rents a room in a house adjoining B'sresidence,and for twoweeks looks into thewindowsofB'supstairsbedroom throughatelescopetakingintimatepictureswithatelescopiclens.AhasinvadedB'sprivacy.”).

130Therecanbean intrusionuponseclusionwithouta trespass.SeeW.PAGEKEETONETAL.,PROSSERANDKEETONONTORTS854(5thed.1984)(footnotesomitted)(“Theprinciple[ofintrusionuponseclusion]has,however,beenextendedbeyond. . .physicalintrusion,and


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aredifficulttodetect.Theymaybeabletostayinspyingpositionforlongerthanhumans.

Theymaybeabletotransmitthedatamorequickly.(Oneinterestingquestioniswhether,

all else being equal, being recorded by a robot and thus not knowingwho is doing the

spying,ismoreorlessoffensivethanbeingrecordedbyahumanwithacamera.Butthatis

aquestionlegitimatelylefttoajury.)

Finally, aswe have noted, because of the newness of robots, evenwhere none of

thesedangersare in fact greater thanpreviously, at least in the short term the riskmay

reasonablyappeartobelarge.Thus,atleastinitially,violentself‐helpwillseem,andoften

maybe,reasonableevenwhentheprivacythreatisnotgreat—orevenextant.

2. Reasons for Not Permitting Self‐Help Against Robotic Intrusions on

Seclusion

The arguments against permitting self‐help in cases of robotic intrusions on

seclusionarenotasstrongasthoseforit.Oneargumentisthatitwillbehardtoengagein

self‐help safely. The fear of injuring others is, however, more an argument against

particularmethods of self‐help than against self‐help in general. One can favor a broad

rightofself‐helpandstillopposeself‐helpintheformofshootinggunsintheairtodown

drones.

Another argument against allowing self‐help is that it will encourage people

concernedaboutdrones to shootdown legitimateoverflights such as a law‐enforcement

drone,thusposingathreattopublicsafety. Or,self‐helpersmightshootdownamanned

extended to eavesdropping upon private conversations by means of wiretapping andmicrophones;andtherearedecisionsindicatingthatitistobeappliedtopeeringintothewindowsofahome,aswellaspersistentandunwantedtelephonecalls.”);seealsoRICHARDA.EPSTEIN,CASESANDMATERIALSONTORTS1050 (8thed.2004) (“The tortof intrusionuponseclusion] does not require a physical trespass on plaintiff’s property, but may beaccomplishedbyeavesdroppingnearanopenwindoworbyoverhearingconversationsbymeansofaparabolicmicrophone.”).Logically,onemightsuspectrobotsthatcameneartoone’sproperty,especiallyifthey

hung around, but absent trespass or a pattern of stalking there will rarely if ever be aprivilege to attack a robot off one’s property even if one suspects that it is spying. Theexistenceofatrespassmakesitmorereasonabletoconcludethattherobotmaybespying.Asageneralmatter theprivilege todefendagainst spying isnota roving commission toattacknearbyrobots.Apersonwouldneedareasonablebelief–evidence–thattherobotwasspyingbeforehavinganyprivilegetoreact.


34

vehiclebymistake.Permittingself‐helpmayencouragepeopletofiregunsintheair,and

maycauseharmwhenadroneisdowned.Andiftheself‐helpermisjudgestheexistenceor

scope of her privilege, she may commit a trespass to chattels or conversion. Self‐help

actionsliketheseposeathreattothestate’smonopolyonforce.

All thesearguments sound in thereasonswhyself‐help is criticizedgenerally, the

reasons why tort law evolved to displace self‐created remedies. The primitive but

prevailing“adhocsystem”ofself‐help, it isoftenargued, inevitably“leadstobreachesof

the peace, violence, and inequities.”131As one state supreme‐court justice declared in

dissent,“[s]elf‐helpmaywellbethefirststeptowardanarchy.”132Thesecritiquesarevalid

in therobotcontext too,but justas these legitimateconcernshavenotproved thedeath

knell for self‐help generally, they should not prevent an appropriate right of self‐help

againstrobots.Thisisespeciallytruebecause,whiletheredonotappeartobeanyreasons

unique to the robot context thatweigh against a broad self‐help right, aswe have seen

thereareuniquefeaturesweighinginfavorofaself‐helpright.

III. StatutoryConsiderationsRelatingtoDrones

So farwe have concentrated on tort law, the traditional common‐law remedy for

civilwrongs.Butstatutesandregulationsbearontheself‐helpissuesinseveralways.To

date,legislaturesandagencieshavefocusedondronesratherthanrobotsingeneral.FAA

rules currently declare the bounds of the airspace in which fixed‐wing aircraft and

helicoptersmayfly.Theseruleshaveclearconsequencesfordefiningthesizeofthecuboid

to which a landowner may claim exclusive possession.133While FAA navigable airspace

131VanderbiltSpecialProject,supranote13,at853.132Duthiev.LewistonGunClub,663P.2d287,298(Idaho1983)(Bistline,J.,dissenting).133Seesupratextaccompanyingnotes83‐93.WhiletheSupremeCourthasnotedthata

law‐enforcement officer could violate the Fourth Amendment while lawfully within thepublicly navigable airspace of the United States, seeFlorida v.Riley, 488 U.S. 445, 451(1989)(“[A]naerialinspectionofahouse’scurtilagemaynotalwayspassmusterundertheFourthAmendmentsimplybecause theaircraft iswithin thenavigableairspacespecifiedby law.”), it seemsclear thatanaction for simple trespassunder state lawwouldnot liewheretheFAAhasdeclaredthatthedefendantwaswithinthenavigableairspace.SeeU.S.CONST.ART.VI,para.2(SupremacyClause).


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regulationisnotaprivacyregulation,itdeclareshowcloseothersmaycometothehome

and thus bears on the home’s solitude. Insofar as the FAA regulation limits when a

landownerhasacauseofaction,italsohelpsshapeherrightofself‐help.

AndiftheFAAisauthorizedtoandundertakestoactintheprivacyarenaitwould

be able to structure the general drone‐related privacy regime through private causes of

action, civil fines, and even crimes. Here, we examine the FAA’s regulatory activities

pertaining todrones.We thendiscusswhether theFAAhas authority to regulatedrone‐

relatedprivacyandwhetheritseemsintentondoingso.Finally,welooktostatelaws,how

theseaffectdrone‐relatedprivacyissues.

A. PotentialFederalAviationAdministrationRegulationofDronePrivacy

1. CurrentFAAApproachtoDronePrivacyRegulation

IntheFAAModernizationandReformActof2012(FMRA),134Congresstaskedthe

FAAwithdevisingrulestoensuretosafeintegrationofdronesintodomesticairspace“as

soonaspracticable,butnot laterthanSeptember30,2015.”135FMRAdirectedtheFAAto

engageintwosetsofrulemaking.ThefirstrequiresthatbyAugust14,2014,theFAAissue

afinalruleonintegrating“smallunmannedaircraftsystems”intothenationalairspace.136

ThesecondrequirestheFAAto(1)developa“comprehensiveplantosafelyacceleratethe

integration of civil unmanned aircraft systems into the national airspace system,”137(2)

provide notice on the proposed rulemaking to implement this comprehensive plan by

August14,2014,138and(3)publishafinalrulebyDecember14,2015.139

TheFAAhasstatedthatitplanstoissuearulefordronesunderfifty‐fivepoundsat

leastayearsoonerthanitwillissuetherulegoverninglargerdrones.140TheFAAhasalso

134Pub. L. No. 112‐95, 126 Stat. 11 (codified as amended in scattered sections of 49U.S.C.).

135Pub.L.No.112‐95,§332(a)(1),126Stat.11,73.136Pub.L.No.112‐95,§332(b)(1),126Stat.11,73.137Pub.L.No.112‐95,§332(a)(1),126Stat.11,73.138Pub.L.No.112‐95,§332(b)(2),126Stat.11,73.139Pub.L.No.112‐95,§332(b)(2),126Stat.11,73.140FED. AVIATION ADMIN., INTEGRATION OF CIVIL UNMANNED AIRCRAFT SYSTEMS (UAS) IN THE

NATIONAL AIRSPACE SYSTEM (NAS) ROADMAP at Appendix C.2, C.6 (2013) [hereinafter FAARoadmap].


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announcedplansalsotoexpediteitscertificationprocess,movingfromadrone‐by‐drone

regimetoamodel‐by‐modelregime.141Inadditiontocertifyingthedroneormodel itself,

theFAAwillrequirepilotandaircrewcertification,buthasyettodefinehowthatprocess

will work.142Pilot certification will be important because the FAA has ruled out

autonomousflightformostdrones.143

FMRAalsodirectedtheFAAtoestablishsixtestrangesfordrones.144Inthewords

oftheFAA,“[t]heoverallpurposeofthistestsiteprogramistodevelopabodyofdataand

operationalexperiencestoinformintegrationandthesafeoperationoftheaircraftinthe

National Airspace System.”145In its most recent rule, the FAA requires all test site

operators to have written and publicly available privacy policies “informed” by Fair

InformationPracticeprinciples,toacceptpubliccommentontheirprivacypolicies,andto

review and update the polices as needed.146 While these policies will not conclusively

establishtheFAA’slong‐termapproach,theyaremeantto“helpinformthedialogueamong

policymakers,privacyadvocates,and the industry.”147Additionally,148 operators will need to

comply with state and local laws that regulate privacy.149This non‐preemption of state laws is

141SeeFAARoadmap,supranote140,§3.4.142SeeFAARoadmap,supranote140§§3.6,4.5,5.5.143SeeFAARoadmap,supranote140,§4.1(“Autonomousoperationsarenotpermitted.

. . .The[pilot‐in‐command]hasfullcontrol,oroverrideauthoritytoassumecontrolatalltimesduringnormalUASoperations.”).

144Pub.L.No.112‐95,§332(c),126Stat.11,73.145UnmannedAircraft SystemTest Site Program, 78 Fed.Reg. 12259 (Feb. 22, 2013).

The FAA received 25 applications for test sites located in 24 different states. FAAconsidered“geography,climate,locationofgroundinfrastructure,researchneeds,airspaceuse,safety,aviationexperienceandrisk”AndselectedtheUniversityofAlaska,theStateofNevada, New York’s Griffiss International Airport, the North Dakota Department ofCommerce,TexasA&MUniversity–CorpusChristi,andVirginiaTechasthetestsites.FAAPress Release, FAA SelectsUnmannedAircraft SystemsResearchandTest Sites, (Dec. 30,2013),http://www.faa.gov/news/press_releases/news_story.cfm?newsid=15576.

146UnmannedAircraftSystemTestSiteProgram,78Fed.Reg.68,360,68,364(Nov.14,2013)(tobecodifiedat14C.F.R.pt91).

147FAARoadmap,supranote140,§1.4.4.148Thislistisnotexhaustive;seetheRule,UnmannedAircraftSystemTestSiteProgram,

78Fed.Reg.68,360,68,364(Nov.14,2013)(tobecodifiedat14C.F.R.pt91),forafulllistofrequirements.

149The Rule requires that Operators comply with “all Applicable Law regarding theprotectionofanindividual’srighttoprivacy.UnmannedAircraftSystemTestSiteProgram,


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significant. Of the states that will play host to the test sites, three have enacted drone

legislation:Oregon,150Texas,151andVirginia.152Thesesiteswillthustesttheexistingstate

policiesandprovidevaluableevidenceofeffectivenessforfuturestateaction.

Whether FMRA entitles the FAA to regulate privacy issues outside of its test‐site

mandatecouldbedebated.TheCongressionalResearchService(CRS)recentlyconcluded

that it would be reasonable for the FAA to interpret FMRA as tasking the FAA with

addressing privacy in its drone‐related rulemaking.153The FAA, however, takes a more

complicatedviewofitsownauthority.Itfoundtheauthoritytoregulateprivacyatthetest

sitesin49U.S.C.§106(l)(6),154whichauthorizestheFAAAdministratortoenterintoatest‐

siteagreement“onsuchtermsastheAdministratormayconsiderappropriate.”155Onthis

logic,onewouldexpectthattheFAAcouldfindauthoritytoregulatedrone‐relatedprivacy

more generally by latching onto the “acceptable standards for operation” language in

FMRA.156IftheFAAcanfindspecificauthoritytoregulateprivacyattest‐sitesinageneral

grantofpower,FMRAwouldseemtoprovideanequallystrongbasisfortheexistenceof

statutoryauthoritytoregulatedrone‐relatedprivacymoregenerally.

78Fed.Reg.68,360,68,364(Nov.14,2013)(tobecodifiedat14C.F.R.pt91).“ApplicableLaw” is defined to mean “(i) a law, order, regulation, or rule of an administrative orlegislativegovernmentbodywithjurisdictionoverthematterinquestion,or(ii)aruling,order,decisionorjudgmentofacourtwithjurisdictionoverthematterinquestion.”Id.

150ActofJul.29,2013,ch.686,2013Or.Laws686(2013).151TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390.152ActofApr.3,2013,ch.755,2013Va.Acts755.153ALISSAM.DOLAN&RICHARDM.THOMPSONII,CONG.RESEARCHSERV.,R42940,INTEGRATION

OFDRONES INTODOMESTICAIRSPACE:SELECTEDLEGALISSUES 22‐27 (2013) The CRS concludesthat while under step one of Chevron FMRA does not expressly authorize the FAA toregulate privacy, “the open‐ended nature of Congress’s instructions to the FAA, coupledwith the prominence of privacy concerns, would likely persuade a court that the FAA’spotentialregulationofprivacyaspartofformalrulemakingisareasonableinterpretationof[FMRA]thatshouldbeaccordeddeferenceunderaChevronanalysis.”Id.at25..

154UnmannedAircraftSystemTestSiteProgram,78Fed.Reg.68,360,68,361(Nov.14,2013) (to be codified at 14 C.F.R. pt 91) (“The FAA’s authority for including the FinalPrivacyRequirementsintheTestSiteOTAsissetforthin49U.S.C.106(l)(6).”).

15549U.S.C.§106(l)(6)(2012).156Pub.L.No.112‐95,§332(a)(2)(A)(i),126Stat.11,73(2012).


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But theFAAdisagrees. It stated in itsRoadmap that its “missiondoesnot include

developing or enforcing policies pertaining to privacy or civil liberties.”157And in

establishingprivacypolicies for the test sites, it stated that its “mission is toprovide the

safest, most efficient aerospace system in the world and does not include regulating

privacy.”158Soeven if itwouldbereasonable for theFAAtoconclude thatFMRAgives it

authority to regulate privacy, its decision that it lacks the authority is entitled to equal

deference.Ifthatinterpretationwaschallenged,whichisperhapsunlikelyduetoArticleIII

standingcomplications,159thequestionwouldbewhetheritisunreasonablefortheFAAto

haveconcludedthatFMRAdoesnotauthorizeregulationofprivacy.

Inanyevent,whetherornottheFAAhasauthorityunderFMRAtoregulatedrone‐

related privacy, it seems that the FAA either believes it lacks that authority or has no

intention of using it. Instead, the FAA seemswilling to have states chart the course for

protection of privacy in the drone context, and shows no appetite to preempt them.160

157FAARoadmapsupranote140,§1.4.4.158UnmannedAircraftSystemTestSiteProgram,78Fed.Reg.68,360,68,361(Nov.14,

2013)(tobecodifiedat14C.F.R.pt91).159Thechallengewouldbepremisedonthetheorythattheplaintiffwasharmedbythe

FAA’s unreasonable interpretation of FMRA to not permit regulation of privacy issues.Courts have historically been skeptical of standing in such cases because of the general,non‐particularizednatureoftheallegedharm.See,e.g.,Lujanv.DefendersofWildlife,504U.S.555(1992).

160 The Joint Planning and Development Agency (“JPDO”), which includesrepresentatives“NextGenerationAirTransportationSystem(NextGen)partneragencies–the Departments of Transportation (DOT), Defense (DoD), Commerce (DOC), andHomelandSecurity(DHS),theNationalAeronauticsandSpaceAdministration(NASA),andthe Federal Aviation Administration (FAA),” JOINT PLANNING AND DEV. OFFICE, UNMANNEDAIRCRAFTSYSTEMS(UAS)COMPREHENSIVEPLAN:AREPORTONTHENATION’SUASPATHFORWARD3(2013) [hereinafter JPDO Plan],, suggests that additional regulation of privacy isunnecessary because “many states have laws that protect individuals from invasions ofprivacy which could be applied to intrusions committed by using a UAS.” JPDOComprehensivePlan at 7. And theFAAnoted a similar reason fornot imposingprivacyrequirements beyond the context of the test sites: “there are many privacy laws andapplicationsof tort lawthatmayaddresssomeof theprivacy issues thatarise fromUASoperations at theTest Sites.”UnmannedAircraft SystemTest SiteProgram,78Fed.Reg.68,360,68,362(Nov.14,2013)(tobecodifiedat14C.F.R.pt91).TheFAAthusconcludedthat it did not need to “monitor a Test Site’s compliance with its own privacy policies”becausetheFAA“expects . . .[the]respectivestate/localoversightbodiestomonitorandenforceaTestSite’scompliancewithitsownpolicies.”UnmannedAircraftSystemTestSite


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Thusitseemslikelythatatleastinthenearfuturestateandlocallawswillcontinuetoplay

theleadingroleinprivacyprotection.

EveniftheFAAwantedtoregulatedroneprivacyissuesgenerally,therewouldstill

beahole in itsauthority:FMRAbars theFAA frompromulgatingrulesregardingcertain

kinds of model aircraft flown for recreational use.161The bar applies where the model

aircraftislessthan55pounds,doesnotinterferewithanymannedaircraft,andisflownin

accordancewitha community‐based setof safetyguidelines.162Theaircraftmustalsobe

flown within the line of sight of the operator and be used solely for recreational

purposes.163Butwhile theFAA isprohibited fromwriting rulesor regulationsgoverning

these aircraft, it is not prohibited from pursuing enforcement actions “against persons

operatingmodelaircraftwhoendangerthesafetyofthenationalairspacesystem.”164Itis

unclearwhethertheFAAwillchoosetoconstruemodelaircraft flownforrecreationalas

including hobbyist drones; in any event this limitation on the FAA’s authority does not

applytorulesconcerningdronesflownforcommercialpurposes.

2. ProposedamendmentstoFAAModernizationandReformActof2012

Severalprivacy‐relatedamendments toFMRAarecurrentlybeforeCongress. The

Drone Aircraft Privacy and Transparency Act of 2013 (“DAPTA”),165 proposed by

RepresentativeEdMarkeyinthe113thCongress,wouldregulatetheprivateuseofdrones,

specifically as to data‐collection requirements and enforcement mechanisms. DAPTA

wouldrequiretheFAAtocreateguidelinesforalldomesticdroneoperations,notjusttest‐

site operations, that include data‐minimization procedures.166The FAA would also be

Program,78Fed.Reg.68,360,68,363 (Nov.14,2013) (tobe codifiedat14C.F.R.pt91).Finally, theFAA stated that “[f]orty‐three stateshavealreadyenactedor are consideringlegislation regulatinguseofUAS.”UnmannedAircraft SystemTest SiteProgram,78Fed.Reg.68,360,68,362(Nov.14,2013)(tobecodifiedat14C.F.R.pt91).

161Pub.L.No.112‐95at§336,126Stat.11,77(tobecodifiedat49U.S.C.§40101).162Id.at§336(a).163Id.at§336(c).164Id.at§336(b).165H.R.1262,113thCong.(1stSess.2013).166Id.at§339.


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requiredtocreateapublicdatabaseofall licenseddrones,thedetailsoftheiroperations,

andadata‐collectionstatementfromeachdroneuser.167

ThePreservingAmericanPrivacyActof2013,168introducedbyRepresentativeTed

Poe,wouldprohibittheuseofdronestocaptureimagesinamannerhighlyoffensivetoa

reasonable person where the individual is engaging in a personal activity under

circumstancesinwhichtheindividualhasareasonableexpectationofprivacy,regardless

of whether there is a physical trespass.169The bill also addresses the admissibility of

evidenceobtainedviadronesurveillance,170prohibitstheweaponizationofdrones,171and

declaresthat“[n]othinginthisActshallbeconstruedtopreemptanystatelawregarding

theuseofunmannedaircraftsystemsexclusivelywithinthebordersofthatState.”172

B. StateDrone‐RelatedLegislation

Substantive173drone‐related legislationhasbeenenactedinninestates:Florida,174

Idaho,175Illinois,176Montana,177North Carolina,178Oregon,179Tennessee,180Texas,181and

Virginia.182Of these states, three—Oregon,183Texas, and Virginia—will host test‐site

operations.184

167Id.at§340(a).168H.R.637,113thCong(1stSess.2013).169Id.at§3119f.170Id.at§3119c.171Id.at§3119h.172Idat§3119i.173Several test‐site states have passed legislation appropriating funds for test‐site

operations.See,e.g.,ActofMay3,2013,ch.49,2013N.D.Laws49.174FreedomfromUnwarrantedSurveillanceAct,2013Fla.Laws33.175ActofApr.11,2013,ch.328,2013Idaho.Sess.Laws328.176ActofAug.16,2013,Pub.ActNo.98‐402,2013 Ill. Laws402sec.5, §48‐3(b)(10)

(prohibits using drone to interfere with hunters or fishermen); Freedom from DroneSurveillanceAct,Pub.ActNo.98‐569,2013Ill.Laws569.

177ActofMay1,2013,ch.377,2013Mont.Laws377.178ActofJul.26,2013,ch.360,2013N.C.Sess.Laws360.179ActofJul.29,2013,ch.686,2013Or.Laws686(2013).180FreedomfromUnwarrantedSurveillanceAct,ch.470,2013Tenn.Pub.Acts470.181TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390.182ActofApr.3,2013,ch.755,2013Va.Acts755.


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Two states—North Carolina185and Virginia186—enacted general moratoria on

public useof dronesuntil July1, 2015.NorthCarolinaprovides an exception in cases of

specificapprovalbythestateChiefInformationOfficer,187whileVirginiaprovidedavariety

ofexceptions,includingemergencysituations,trainingofofficers,andtrafficassessment.188

Virginia189also,alongwithOregon,190bannedthe installationofweaponsongovernment

drones.

Seven191of the nine states to have passed drone legislation—all except North

CarolinaandVirginia,whichinsteadenactedgeneralmoratoriaondrones—haveincluded

a warrant requirement for government surveillance via drone.192Several of these laws

provideforexceptionsincaseofterroristactivity193orwhere“swiftaction”isrequiredto

prevent harm to human life.194Montana195and Oregon196bar the use of information

183WhileOregonwillnotplayhosttoatestsiteofitsown,theUniversityofAlaskaplansto set up test site operations there. FAA Press Release, FAA SelectsUnmannedAircraftSystems Research and Test Sites, (Dec. 30, 2013),http://www.faa.gov/news/press_releases/news_story.cfm?newsid=15576.

184FAA Press Release, FAASelectsUnmannedAircraftSystemsResearchandTestSites,(Dec. 30, 2013),http://www.faa.gov/news/press_releases/news_story.cfm?newsid=15576.

185ActofJul.26,2013,ch.360,2013N.C.Sess.Laws360§7.16(e).186ActofApr.3,2013,ch.755,2013Va.Acts755sec.1,§1.187ActofJul.26,2013,ch.360,2013N.C.Sess.Laws360§7.16(f).188ActofApr.3,2013,ch.755,2013Va.Acts755sec.1,§1.189ActofApr.3,2013,ch.755,2013Va.Acts755sec.1,§1.190ActofJul.29,2013,ch.686,2013Or.Laws686§10(2013).191Texasdoesnotexplicitlyrequireawarrant.Thestatuteenumeratesnineteenlawful

usesofdrones, oneofwhich is surveillancewith awarrant.TexasPrivacyAct, ch. 1390,2013 Tex. Gen. Laws 1390 sec. 2, § 423.002(a)(7). It stands to reason, then, thatunwarrantedsurveillanceisnotlawful.

192FreedomfromUnwarrantedSurveillanceAct,ch.2013‐33,2013Fla.Laws33sec.1,§4(b); Act of Apr. 11, 2013, ch. 328, 2013 Idaho. Sess. Laws 328 sec. 1, § 21‐213(2)(a);FreedomfromDroneSurveillanceAct,Pub.ActNo.98‐569,2013Ill.Laws569§15(2);ActofMay1,2013,ch.377,2013Mont.Laws377sec.1,§1(a);Actof Jul.29,2013,ch.686,2013Or.Laws686§3(1)(a)(2013);FreedomfromUnwarrantedSurveillanceAct,ch.470,2013Tenn.Pub.Acts470sec.1,§d(2);TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§423.002(a)(7).

193See,e.g., Freedom fromDroneSurveillanceAct,Pub.ActNo.98‐569,2013 Ill. Laws569§15(1).

194See,e.g.,FreedomfromUnwarrantedSurveillanceAct,ch.2013‐33,2013Fla.Laws33sec.1,§4(c).


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obtainedthroughdronesurveillancetoestablishprobablecause.Tennessee,inadditionto

itswarrantrequirement,explicitlydeclaresthatdronesurveillanceconstitutesasearch,197

presumablytoavertanyattempttoargueotherwise.

TheIllinois,Oregon,Tennessee,andTexasstatutesallcontaindataminimizationor

reporting requirements. Illinois requires law‐enforcement agencies to delete recorded

informationwithinthirtydays198unlessthereisreasonablesuspicionthattheinformation

contains evidence of criminal activity199or is relevant to an ongoing investigation or

criminal trial.200The law also bans disclosure of such information subject to the same

exceptions.201The Oregon statute bans the disclosure of such information by law‐

enforcement agencies subject to certain emergency exceptions.202The Tennessee statute

requires law‐enforcement agencies to delete information within twenty‐four hours of

recording, but this rule applies only to information obtained in violation of the Act, not

information lawfully obtained.203The Texas statute does not contain data‐minimization

requirements,butdoescontaindetailedreportingrequirements.204TheActrequireseach

statelawenforcementagencytoprovidetothegovernorandeachstatelegislatorareport

includingdetailson“thetypeofinformationcollectedonanindividual,residence,property,

orareathatwasnotthesubjectofa lawenforcementoperationandthefrequencyofthe

collectionofthisinformation.”205

195ActofMay1,2013,ch.377,2013Mont.Laws377sec.1,§2.196ActofJul.29,2013,ch.686,2013Or.Laws686§11(2)(2013).197FreedomfromUnwarrantedSurveillanceAct,ch.470,2013Tenn.Pub.Acts470sec.

1,§g(1).198FreedomfromDroneSurveillanceAct,Pub.ActNo.98‐569,2013Ill.Laws569§20.199Freedom from Drone Surveillance Act, Pub. Act No. 98‐569, 2013 Ill. Laws 569 §

20(1).200Freedom from Drone Surveillance Act, Pub. Act No. 98‐569, 2013 Ill. Laws 569 §

20(2).201FreedomfromDroneSurveillanceAct,Pub.ActNo.98‐569,2013Ill.Laws569§25.202ActofJul.29,2013,ch.686,2013Or.Laws686§§3,5,6(2013).203FreedomfromUnwarrantedSurveillanceAct,ch.470,2013Tenn.Pub.Acts470sec.

1,§f.204TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§423.008.205TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§423.008(b)(4).


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Severalof thestatutescontainprovisionsgoverningprivateuseofdrones.Oregon

makesitacrimetouseadroneasaweapon206orinterferewithanyFAA‐licenseddrone;207

Texas makes it a crime to capture, possess, or disseminate images of unconsenting

individualsundercertaincircumstances.208TheTexasstatutealsolistsnineteensituations

inwhichitispermissibletocaptureimageswithdrones.209

Five of the states—Florida, Idaho, Oregon, Tennessee, and Texas—provide civil

causes of action in cases of certain violations. Florida provides a cause of action to

individualswhohavebeensurveilledby law‐enforcementdrones inviolationof theAct’s

prohibitions.210Idaho provides a cause of action against law‐enforcement officers or

privateindividualsforgatheringofimagesinviolationoftheAct.211Oregon,inadditionto

criminalizing interference with any FAA‐licensed drone, provides a cause of action for

individuals harmed by such interference.212The Oregon statute also creates a right of

action for overflights below 400 feet if there ismore than one overflight and the drone

operator has been warned.213There is a takeoff‐and‐landing exception to this cause of

action,214but where successful the statute allows for damages, an injunction, and even

attorney’sfees.215Oregon’sstatutealsoauthorizesitsattorneygeneraltobringactionsfor

nuisances and trespasses arising out of drone operations within the state.216Tennessee

provides a cause of action against law‐enforcement agencies that violate the Act’s

surveillance prohibitions.217Texas provides for a privacy cause of action against an

206ActofJul.29,2013,ch.686,2013Or.Laws686§13(1)(2013).207ActofJul.29,2013,ch.686,2013Or.Laws686§13(2)(2013).208TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§§423.003,423.004.209TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§423.002(a).210FreedomfromUnwarrantedSurveillanceAct,ch.2013‐33,2013Fla.Laws33sec.1,§

5.211ActofApr.11,2013,ch.328,2013Idaho.Sess.Laws328sec.1,§21‐213(3).212ActofJul.29,2013,ch.686,2013Or.Laws686§14(2013).213ActofJul.29,2013,ch.686,2013Or.Laws686§15(1)(2013).214ActofJul.29,2013,ch.686,2013Or.Laws686§15(2)(2013).215ActofJul.29,2013,ch.686,2013Or.Laws686§§15(3),(4)(2013).216ActofJul.29,2013,ch.686,2013Or.Laws686§15(5)(2013).217FreedomfromUnwarrantedSurveillanceAct,ch.470,2013Tenn.Pub.Acts470sec.

1,§e.


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individualwho captures an imageof property or the property owner or tenantwith the

intenttoconductsurveillance.218

As mentioned above, Oregon’s statute creates a civil cause of action for drone

overflightbelow400feetif(1)therehasbeenapreviousoverflightbelow400feet(2)after

whichthelandowner“notifiedtheowneroroperatorofthedronethatthe[landowner]did

not want the drone flown over the property at a height of less than 400 feet.”219This

provision has the virtue of clarifying the extent of air rights and also of rejecting the

anomaloushybridtrespass‐nuisancestandardoftheRestatement(Second)ofTorts.220On

the other hand, the requirement that a landowner notify a drone owner/operator as a

prerequisitetosuitignorestherealitythatthelandowneroftenmayhavegreatdifficultyin

figuringouttheidentityoftheowner/operatorofremotelyoperatedprivatedrones.(Itis

an interesting question whether a landowner could satisfy the notice requirement by

simplypostinga“NoDrones”sign,andifsoatwhatanglethesignwouldhavetobeposted

tobeeffective.)

The state statutes that create private causes of action should in theory create by

implication a concomitant privilege of self‐help. Legislators are generally presumed to

makenewlawsagainstthebackgroundofexistinglaws.221Inotherwords, legislatorsare

presumed to know the state of the law as it exists when they draft new laws. Thus,

legislators could be presumed to know that tort causes of action generally provide the

victimwith some rightof self‐help, and it could thereforebeargued that they shouldbe

presumedtohaveintendedtoprovideaself‐helpright.

An additional issue raised by the statutes that create a civil claim against a

government agency or official is whether those statutes permit some form of self‐help

againstagovernmentdrone.That is,does the fact thatadrone isoperatedby theBoise,

218TexasPrivacyAct,ch.1390,2013Tex.Gen.Laws1390sec.2,§423.006.219ActofJul.29,2013,ch.686,2013Or.Laws686§15(1)(2013).220Seesupra§II.C.2.b.221Astoria Fed. Sav.& LoanAss'n v. Solimino, 501U.S. 104, 108 (1991) (“Congress is

understoodtolegislateagainstabackgroundof[thecommonlaw.]Thus,whereacommon‐lawprinciple iswell established, . . . the courtsmay take it as a given thatCongresshaslegislatedwithanexpectationthattheprinciplewillapplyexceptwhenastatutorypurposetothecontraryisevident.”)(citationsomitted)(internalquotationmarksomitted).


45

IdahoPoliceDepartmentinsteadoftheIdahoStatesmannewspaperdeterminewhethera

personbeingsurveilledisentitledtoself‐help?Oneofthestatestatutesthatprovidessuch

a cause of action against public entities—Oregon’s—does expressly declare that it is a

crimetointerferewithagovernmentdrone,222takingtheissueoffthetableforthatstate,

butnottheothers.

IV. ImprovingtheLawofHuman‐RobotInteractions

ItisclearthatapersonintheUnitedStateshasalegalrighttodefendherselfagainst

aperceivedor actual physical threat froma robot. Other aspectsof self‐defenseagainst

robots—particularlythoserelatingtodefendingpropertyorprivacy—aresignificantlyless

clear.Basedonoursurveyabove,wehaveidentifiedsevenspecificlegalissuesrelatingto

unpleasantrobot‐humaninteractions.223Notably,eachofthesesevenissuesinvolvessome

kindofuncertainty.Twooftheissuesinvolveuncertaintyastoeitherthelaw(theextent

of the self‐defense privilege in response to intrusions upon seclusion) or legal fact (the

extent of the aerial boundary to property). But the others five flow from a reasonable

ordinary person’s understandable uncertainty about robots in general and about the

capabilitiesandintentionsoftherobottheyareconfrontedwith inparticular. Belowwe

offer proposals designed to reduce this uncertainty. These proposals will minimize the

needforviolentself‐helpbutalsoclarifythecircumstanceswhereitwouldbeappropriate.

A. ClarifyStateRulesonVerticalCurtilage–MakeaNationalRule?

Horizontally, thecurtilageofaproperty is thearea“immediatelysurroundingand

associatedwith the home.”224In law, the curtilage is considered to be “part of the home

itself forFourthAmendmentpurposes.”225Thedimensionsoftheequivalentaerialspace

222Oregondeclares ita felonynot just to interferewithagovernmentdrone,butwithanydrone licensedby theFAA.Actof Jul.29,2013, ch.686,2013.Or.Laws686§13(2)(2013).

223Seesupra§I(listingsevenissues).224Floridav.Jardines,133S.Ct.1409,1414(2013).225Floridav.Jardines,133S.Ct.1409,1414(2013);Oliverv.UnitedStates,466U.S.170,

180(1984).


46

aboveahomeanditshorizontalcurtilage,whatonemightcalltheverticalcurtilage,226are

notasclearasthoseofthehorizontalone.227FAArulesonminimumnavigableheights228

alsoplayapartmajorpart.StatescouldintheorysetanupperboundlowerthantheFAA

rules.229Oregon recently set an upper bound of 400 feet for drone overflights in certain

circumstances,230but this upper bound is not lower than any relevant current FAA rule

becausetheFAAdoesnotcurrentlyhaveaheightrulefordrones.231Anythinginexcessof

FAArulesonnavigableairspacewillbepreempted.

AstheFAAcurrentlydoesnothaveauthoritytoregulatehobbyistdrones,themain

sourcesofregulationfornon‐commercialdronesarestatecommonlawandstatestatutory

law. Meanwhile,however, thepeopleon thegroundmay find itdifficult todistinguisha

(legal) hobbyist drone from an (illegal) low‐flying commercial newsgathering/paparazzi

226According to Brendan Peters, FourthAmendmentYardWork:Curtilage'sMow‐LineRule,56STAN.L.REV.943,959nn.96‐96(2004),theU.S.SupremeCourt"hasneveradoptedtheconceptof'verticalcurtilage.'Instead,curtilageasviewedfromaboveisanalyzedundertheKatz[v.UnitedStates,389U.S.347(1967)]reasonablenessframework.”

227Thereisstillsomefundamentaluncertaintyabouttheextentofverticalequivalentofcurtilage. SeeFloridav.Riley,488U.S.445(1989)(holding thatobservation frompolicehelicopterflyingat400feetdidnotrequirewarrant);DowChemicalv.UnitedStates,476U.S.277,239(1986)(holdingthatobservationfromaltitudeof2000feetwasnotakintoenteringintocurtilageandthusdidnotrequirewarrant);Californiav.Ciraolo,476U.S.207,213 (1986) (holding that fixed‐wing observation of the curtilage from "public navigableairspace," 1000 feet above ground, didnot requirewarrant). Seealso Commonwealth v.Oglialoro,547A.2d387(Pa.Super.Ct.1988)aff'd,579A.2d1288(Pa.1990)(holdingthathelicopter operating in “nonnavigable airspace” 50 feet above property was intrusiveenough to violate 4th Amendment right against unreasonable warrantless search); id. at392 (Kelly, J., concurring) (discussing "vertical curtilage"). In contrast, the concept ofhorizontal curtilage both has “ancient and durable roots,” Florida v. Jardines, 133 S.Ct.1409,1414 (2012), and, theSupremeCourt tell us, “is ‘easilyunderstood fromourdailyexperience.’”Id.at1415(quotingOliverv.UnitedStates,466U.S.170,182,n.12(1984).).

228Seesupra§II.C.2.a.229At some point, if the boundarywere set low enough to interferewith the use and

enjoyment of the property the state rule might infringe the Takings Clause of the FifthAmendment.SeeCausbyv.UnitedStates,328U.S.256(1946).

230ActofJul.29,2013,ch.686,2013Or.Laws686§15(1)(2013).231Seesupratextaccompanyingnote91.


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drone.232Theymaythushaveahardtimedeterminingtheirrightofself‐help.Otherthan

this, at present the problem of vertical curtilage is not acute. Nevertheless, it is only a

matter of time before the FAA permits drone flights over roads, public spaces, and

homes233—theonlyissueistheminimumaltitude.States,orpreferablyaCongress,could

avoid both confusion and litigation if they were to establish a clear minimum height

restriction for drone overflights of private property that covered both hobbyist234and

commercialdrones.

B. ClarifytheRighttoSelf‐DefenseinResponsetoIntrusiononSeclusion

Asnotedabove,235wehavefoundnocasesdelineatingtheextentoftheprivilegefor

self‐helpinthefaceofanintrusionintoseclusion.Logic,andthegeneralsweepoftortlaw,

suggests that reasonable self‐help should be privileged, but as we noted above, it is

remarkably difficult to determine how much force would be reasonable given the very

great uncertainties about a robot’s, and especially a drone’s, spying capabilities and

intentions.Intheshortrun,thatuncertaintylikelywillbefoundtojustifyquiteenergetic

self‐helpefforts.Statesshouldprovidesomeguidancebystatuteorelsepeoplemayshoot

firstandaskquestionslater.

C. ReduceUncertaintyaboutRobotsGenerally

Apersonconfrontedwitharobotictrespasser,orarobotthatmightbeaspy,ora

property‐damaging robot, will in many cases have genuine and understandable doubts

abouttherobot’scapabilitiesandintentions.When,asaresultofthisuncertainty,aperson

232To the extent that genuine news‐gathers were regulated more stringently thanhobbyists who presented no greater danger or disruption to the people and propertybelow,thenews‐gathersmighthaveaquitesubstantialFirstAmendmentclaimaswell.

233Notethattheoverflightissueisdistinctfromthedeliveryissue.IfanAmazondroneor a Taco copter is making a delivery in response to an order, the homeowner haspresumablyconsentedtotheintrusionandthereisthusnotrespassissue.(Surprisegiftsraisetrickierissues.)AnyrelevantFAAruleswouldstillapply.

234Note that while FAA does not have authority to regulate hobby drones, seeF.A.A.ModernizationandReformActof2012,Pub.L.No.112‐95at§336,126Stat.11,77(tobecodified at 49 U.S.C. § 40101), Congress does, subject only to whether this would be agenuineregulationofinterstatecommerce.

235Seesupra§II.D.


48

assumestheworstaboutwhattherobotisdoingorisgoingtodo,herunderstandablelack

of informationaboutwhattherobotmightbecapableofwill,undersomecircumstances,

provideabasis fora legal judgmentthatherbeliefwas, in law,reasonable.236Ordinarily

whenconfrontedwithnewtechnologies,courtsandjuriestendtofindthatitisreasonable

forpeopletofearthem:thuswewouldexpectthatrobots,atleastforawhile,willbeheld

reasonably toappear toposegreater threats than theyactuallydo. At least for thenear

future, so longas thepublic remainsunfamiliarwithand thuspotentiallyuncomfortable

aroundrobots,judgesandjuries237likelywillfind—andwouldbejustifiedinfinding—that

a great level of caution and suspicion was “reasonable.”238 Seeing fear and caution as

normalwillthustendtopushjudgesandjuriestowardsacceptingamoremuscularformof

self‐defense than society as a whole might decide to find reasonable once robots have

become domesticated and commonplace. And it is likely to be a higher level than robot

ownersandoperatorswouldlike.

Itisnotsurprisingthattheintroductionofapotentiallydangerousnewtechnology

into homes, offices, and public spaces might create some uncertainty. But if indeed

uncertaintyisthefeaturecommontoeachoftheselegalproblems,thenitfollowsthatthe

way to eliminate the problems—or at least reduce their severity—will be to remove, or

reduce, the degree of uncertainty reasonably felt by people who have unexpected or

unwantedencounterswithrobots.

236Foranexampleofonecitizen’sreactiontofindingadroneoutsideherwindow,seeKathryn A. Wofe, Dianne Feinstein spots drone inches from face, POLITICO (Jan.16, 2014),http://www.politico.com/story/2014/01/senator‐dianne‐feinstein‐encounter‐with‐drone‐technology‐privacy‐surveillance‐102233.html.

237Juriesfindfacts;judgesdecidequestionsoflaw.Inaciviltrial,whetherabelieforanactionwasreasonableunderthecircumstancesisusuallyaquestionoffactforajuryunlesseitherthepartiesbothwaivetheirrighttoajurytrialor,inthecaseofjurytrial,thejudgeresolves the question as a matter of law by holding that no reasonable jury could findotherwise.

238An alternate possibility is that courtsmight consider the operation of a dangerousrobotininhabitedareastobean“ultrahazardousactivity.”An“ultrahazardousactivity”isanactivitythatnecessarilyinvolvesariskofseriousharm,whichcannotbeeliminatedbytheexerciseoftheutmostcare,andthatisnotamatterofcommonusage. Seesupratextaccompanyingnotes36‐39.


49

In general, uncertainty about robots will be reduced either by (1) limiting the

capabilitiesthatrobotmakersmaylegallygivetheircreations,or(2)bycreatingpractical

or legalmechanismsbywhich robots clearly announce their presence, their capabilities,

andperhapstheirintentions.

1. ProhibitArmedRobots

AssumingtherearenoSecondAmendment issues involved,239itwouldbeentirely

proper forstate legislaturesorCongress tomakerules forbiddingequippingrobotswith

weaponrysuchasgunsoranti‐personneldevicessuchasTasers.240Ablanketnationalrule

makingitillegaltoarmarobotwouldmakeitfarlessreasonableforapersontofearthata

robotwasintendingtoattackher.Itisalwayspossiblethataroguerobothobbyistmight

haveequippedRobbywithasix‐shooterorastungun,butwithoutsomereasontobelieve

Robbyispacking, itwill inallbutthemostexceptionalcasebeunreasonableto fearthat

sortofattack.

Prohibitingarmedrobotswillhavetheadditionalvirtueofweakeningthecasefor

finding thatoperationofa robotoutside the lab isanultrahazardousactivity. Thereare

substantial reasons to think that operating an armed robot might be ultrahazardous,

startingwiththefactthattherobotisdesignedtobedangeroustopeople.Eveniftherobot

is completely under the control of the remote operator there is always the chance that

someonemightjamthecontrols,hacktherobot’ssoftware,orthatitmightmalfunctionin

somemanner. Plus, if thearmedrobothasanysortofautonomythatcouldconceivably

includefirecontrol,thesciencefictionplotsjustaboutwritethemselves.Thelegalsystem

239TheSecondAmendment,U.S.CONST.AMEND.II,issuewouldnotbetherobot’srighttobearmed,butrathertherobot‐owners’righttoanarmedrobot.Giventhatrobotsoperateataremovefromtheircontroller,nottomentionpotentiallyautonomously,onecouldbeforgivenforwonderinghowonecouldseriouslyarguethatdeployinganarmedrobotwas“bearingarms” inaConstitutional sense. Foranattemptnonetheless todo just that, seeDanTerzian,TheRighttoBear(Robotic)Arms,117PENN.ST.L.REV.755(2013)(proposing,interalia,are‐interpretationofDistrictofColumbiav.Heller,554U.S.570(2008)).

240 This is, alas, far from a fantastic suggestion. See, e.g.,https://www.youtube.com/watch?v=M1KdNCMWbU4 (video of a Taser‐equipped dronebuiltbytheChaoticMooncorporationdeliveringan80,000voltshocktoavolunteer–thefirm’s intern); Susanna Kim, Texas Start‐Up Tasers Intern Via Stun‐Copter to SparkDiscussion About Tech at SXSW, http://abcnews.go.com/Business/intern‐tasered‐drone‐sxsw‐explains‐feels‐zapped/story?id=22848505(Mar.10,2014).


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islikelytobeverysensitivetothesepossibilitiesnomatterhowmanysafetyprecautions

areincludedintherobot’sdesign.

2. GiveNoticeofRobotCapabilities

Even if robots areunarmed (ordisarmed), other concerns including fear of being

rolledoverbyarobot,orfearofhavingadronecrashintoone,maystillrisetothelevelof

reasonableness. Personal safety fears that do not prove to be grounded in fact should,

however, be cured by time. In the case of robots, however, time alonewill provide only

partialcureforuncertaintyastowhatagivenrobotcando.Itislikelythatcertaintypesof

robots—autonomous cars for example—will be branded in a manner that makes them

distinct.Theywillhaverecognizableshapes,andbeardistinctivecorporatelogos.If,say,

Google self‐driving cars have an excellent safety record after hundreds of thousands or

millionsofmilesontheroad,thenitshouldbecomeprogressivelylessreasonabletofear

them. On theotherhand, ifGoogleself‐drivingcarswere tobecomeknown forcarrying

automatedwi‐fisniffersthatattempttobreakintotoeveryprivatenetworktheypass,241it

wouldbecomeveryreasonabletoworryeverytimeonewentpast,nottomentionifone

tarriedinfrontofthehouse.Evenaftermostpeoplebecomefamiliarenoughwithrobotsto

associate capabilities with different types, much as most people today can distinguish

between a bus and a backhoe, therewill still be issues of perception and identification,

particularlyregardingaerialrobots.

Fromaneconomicperspective,therobotoperatorisclearlytheleastcostavoiderin

thisscenario: itwouldbefarmoreexpensivetoexpecteverylandownerandoccupierto

invest in gear capableofdiscerning theparticularsof every robot flyingoverhead. The

overall cost to society would be much less if the robot operator had the burden of

advertisingtherobot'scapabilitiesthroughmarkings,lights,orothermeans.

Thus, the best way to create a balance—to ensure that drones are not unduly

attacked and that people are only duly worried about what drones are doing—is to

241Although it did not involve robots or self‐driving cars, Google’s national mappinginitiative includedasecretprogramtocapture informationaboutnot just the locationofpublic wi‐fi networks but also private wi‐fi and even to copy traffic carried on thosenetworks.SeeDavidKravets,AnIntentionalMistake:TheAnatomyofGoogle’sWi‐FiSniffingDebacle, WIRED (May 2, 2012), http://www.wired.com/threatlevel/2012/05/google‐wifi‐fcc‐investigation/.


51

standardize howdrones, and other robots also, declare their capabilities and intentions,

thuschangingwhatfearsarelegallyandmorallyreasonable.Adronewithcamerasorwi‐fi

sensors is a greater privacy threat than one lackingmeans of recording or transmitting

personal information. Theordinaryperson,however,cannotbeexpectedtoevaluatethe

potential harmfulness of a drone as it buzzes along at thirty feet in the air,much less a

hundred.

Mandatory—andeffective—noticeisthuscriticalbothexanteandexpost.Exante

noticeenablesmoreaccuratewarningsofwhattherobotisabletodo,thusinforming—or

defanging—threatassessment.Whateverrulesweadopt,wewillneedstandardsdefining

both robot harmlessness and common types of danger, and standardized means of

advertising both harmlessness and dangerousness. Developing these grammarsmay be

especiallychallengingforrobotswithsomeautonomy,andevenmoresoforthosecapable

of emergentbehavior. In addition, expostnotice combinedwith a licensing regimewill

helpconnectamalfeasantrobottoitsowneroroperator.

a. ExAnteNotice:Warnings

The ideaofenacting legalrulesrequiring theoperatorofscarynewtechnology to

warnthepublicaboutit isfarfromnew. Theposterchildforwhatnowseemsexcessive

warningislikelytheso‐calledRedFlagActof1865,242whichrequired

[e]veryLocomotivepropelledbySteamoranyotherthanAnimalPoweronany Turnpike Rod of public Highway [to have at least three drivers orconductors.] . . . [O]neof suchPersons,while anyLocomotive is inmotion,shallprecedesuchLocomotiveonFootbynotlessthanSixtyYards,andshallcarryaRedFlagconstantlydisplayed,andshallwarntheRidersandDriversofHorsesof theApproachof suchLocomotives, and shall signal theDriverthereof when it shall be necessary to stop, and shall assist Horses, andCarriagesdrawnHorses,passingthesame.243

TheoriginalRedFlag rule lastedseventeenyears,beingamended in1879 torequire the

flagmantobeonlytwentyyardsinfrontofamotorcar.244Itseemssillynow,butitsday,

the Red Flag Act may have seemed a reasonable response to the risk of stampeding

242LocomotivesAct,1865andLocomotivesAct,1861,28&29Vict.,c.83(1865)(Eng.).243Idat§3.244SeeHighwaysandLocomotives(Amendment)Act,41&42Vict.,c.77at§29(1878)

(Eng.) (amending section three of Locomotive Act, 1865). The Act made no distinctionbetweenautomobilesandlocomotives.


52

livestockthatcouldbeterrifiedbytheloudnoisesandoccasionalsteamblastsfromearly

boilerengines.245

TheRedFlagActhadanotherprovision,however,thatlooksmuchmoremodern.In

additiontotheflagman,theActrequiredlights:

Sixthly, any Person in charge of any such Locomotive shall provide TwoefficientLightstobeaffixedconspicuously,OneateachSideontheFrontofthesame,betweentheHoursofOneHourafterSunsetandOneHourbeforeSunset.246

The ideaof requiring cars, andnowplanesandhelicopters, tohave running lightswhen

operating in the dark lives on—and needs to be extended to any robots thatwill travel

outdoors,especiallyaerialrobots.

In order for a person to be able to make an accurate threat assessment of a

trespassingornearbyrobot,somethingmustwarnthatpersonoftherobot’scapabilitiesor

giveaccurateindicationofitsrelativeharmlessness.Asolidbluelight,forexample,might

indicatetheabsenceofanysurveillancedevice;flashingredandbluecouldmeanapolice

drone (don’t shoot that); other colors might indicate various surveillance capabilities.

Placingthedutyonthedroneownerbyrequiringadeclarationofharmlessnessinorderto

enjoyasafer—butperhapsnotentirelysafe—harborwouldfollowtheprecedentsetbythe

international conventions regulating civilian aircraft.247 Similarly, a rule requiring clear

245SeeARVIDLIND,PRESTONTUCKERANDOTHERS:TALESOFBRILLIANTAUTOMOTIVEINNOVATORSAND INNOVATIONS 113 (2011). In fact, however, “A Parliamentary committee in 1873determined that amanwalking 60 yards ahead of a car andwaving a red flagwas notparticularly effective since roads were often busy enough with horses and carts andbicyclesandwhatnot that themangot lost in the traffic.Also,wavinga red flagonbusystreets tended to frighten horses more than it warned their owners of an approachingdanger.” The New London to New Brighton Antique Auto Run,http://www.solivant.com/oldcars/.

246LocomotivesAct,1865,supranote242,at§3.247Under international humanitarian law, medical aircraft that identify themselves

during armed conflict by using a flashing blue light are entitled to protection and evenspecialassistanceandlandingrights.SeeProtocoladditionaltotheGenevaConventionof12August1949,andRelatingtotheProtectionofVictimsofInternationalArmedConflicts,openedforsignatureDec.12,1977,art.6,1125U.N.T.S.3. SeealsoMichelBourbonniere,LouisHaeck,MilitaryAircraftAndInternationalLaw:ChicagoOpus3,66J.AIRL.&COM.885,965 (Summer 2001). For a general discussion of the (relatively narrow) application ofinternational law of armed conflict to the marking of remotely piloted vehicles see


53

markings and lights to distinguish official robots from civilian ones would follow the

precedents that restrict distinctive lighting combinations to emergency vehicles and law

enforcement.Thereiscurrentlynointernationalstandardforcarandtruckemergencyand

police lights248and indeed domestic U.S. practices vary somewhat by state or even

locality,249butoneoftheadvantagesofwritingarulenow,beforelargenumbersofdrones

aremanufactured and deployed, is thatwe could set a consistent national (and, ideally,

international)standard.

Thislastpointbearsemphasis:theperfecttimetoestablishanationalstandardfor

mobile robot warning lights is now, before there is a substantial installed civilian base

withoutstandardwarningequipment.Themorethatprivateownersdeployaerialdrones

orland‐basedmobilerobotswithoutstandardlights,thegreaterthecostofretrofittingthe

lights later—or the larger the class of unlighted and grandfathered robots, potentially

underminingtheeffectivenessofanywarningsystem.

Analternative,muchmoreexpensive,rulewouldbetorequirethatdronesatleast,

andperhaps autonomous land‐based robots also, carry something akin to theAutomatic

generallyIanHenderson,InternationalLawConcerningTheStatusAndMarkingOfRemotelyPilotedAircraft,39DENV.J.INT'LL.&POL'Y615(2011).

248AlthoughtheUNConventiononRoadTraffic(1968)andtheUNConventiononRoadTraffic (with1993amendments)Art.2& Id.AnnexV§42,andalsoEURegulation65,E/ECE/324/Rev.1/Add.64/Rev.2at¶¶1.1,2.1,discusstheuseofblueandamberas“specialwarninglamps”andred,whiteorblueforflashinglamps,thereisnoeffectiveinternationalstandard color for emergency vehicles, and there are still many countries with othersystemsevenwiththeEU.“Thereiscurrentlynouniformapproachamongall27MemberStates on the colour and use of emergency lights on ambulances and fire engines; thecolour used may differ from one Member State to the other.” European Parliament,CommitteeonPetitions,NoticetoMembers,Petition1268/2011byAlbertoLemosdaSilva(Portuguese),onthelackofuniformityofemergencysignsinambulancesandfirefightingvehicles(May20,2012)(complainingofnon‐uniformityofSpanishemergencyvehicles).

249Compare,e.g.ColoradoRev.Stat.§42‐4‐213(2)(flashingoroscillatingredrequiredforemergencyvehiclesandreservedtotheiruse;blue,white,orblueincombinationwithwhite allowed as optional additions) with Connecticut Gen. Stat. § 14‐96p (reservingflashing blue and green for officially permitted uses including volunteer ambulances;flashing red for vehicles transporting studentswith disabilities and for ambulances andschool buses; flashing red or white or amber for certain official vehicles on the way toemergencies;flashingorrevolvingwhiteforfirevehicles).


54

dependentsurveillance‐broadcast(ADS‐B)transponderscurrentlyrequiredforaircraft.250

This device would broadcast information including a unique identification number,

location, altitude, and velocity, and perhaps basics about the capabilities of the robot.

Transpondershaveadvantagesanddisadvantagesovercoloredlightsinthatatransponder

sends alphanumeric information, which can be detected from further away, and when

decoded is easier to record andharder tomisread than a light. The information‐bearing

potential of lights also is reduced by the color blindness of a substantial fraction of the

population.251On the other hand, decoding transponder information requires equipment

not commonly found in the home.252Even if that equipment were issued to first

responders, flying intruders at least might be long gone before the reader reached the

scene.Transponders,however,areexpensive253(althoughthereaderslessso254),andare

substantiallyheavierthanafewsmallLEDlights.

YetanotherpossibilitywouldbetorequireRFIDchipsindrones,asthesearemuch

lighterweight. Passive RFID chips aremuch less expensive than transponders, but their

range is also much shorter, commonly only a few meters. Battery‐powered RFID tags,

250SeeFederalAviationAdministration,AutomaticDependentSurveillance—Broadcast(ADS–B)OutPerformanceRequirementsToSupportAirTrafficControl(ATC)Service,14C.F.R.Part91(definingADS‐Brequirementsforaircraftandrequiringaircraftcarrythemby2020).

251“According to 2006 estimates from the Howard Hughes Medical Institute, around7.0% of the male population and 0.4% of the female population cannot differentiatebetweenredandgreenortheyperceiveredandgreendifferentlytootherpeople.”AnanyaMandel, Color Blindness Prevalence, NEWS MEDICAL, http://www.news‐medical.net/health/Color‐Blindness‐Prevalence.aspx.

252Another,fartooexpensive,alternativewouldbetosetupanationalgridakintoair‐trafficcontrolfordrones.

253Currentprices foranADS‐Btransponderforanaircraftareabout$10,000. See JimMoore, Many Choices for ADS‐B equipage, AOPA (Mar. 28, 2013),http://www.aopa.org/News‐and‐Video/All‐News/2013/March/28/Many‐choices‐for‐ADS‐B‐equipage.Lesscapabletranspondersarelessexpensive,withModeCtransponderssellingforunder$2000.

254 See, e.g. Wings & Wheels Inc, price list,http://www.wingsandwheels.com/Transponders%20encoders%20PCAS%20MRX%20XRX%20TTPAS%20Becker%20TRIG%20Microair.htm(startingataround$500).


55

however,alreadycanachievearangeofupto300feet.255Untiltheordinarypersonhasan

RFID reader, this solution too will be somewhat limited in value, but RFID readers are

about$500.256

The lowest‐cost, but also only partially effective, alternative would be to require

drones,andespeciallyindoorandland‐basedrobots,tobeardistinctiveexteriormarkings

givingnoticeof their capabilities. Themarking strategymightbe as simpleashavinga

reservedsafe‐harborcolorforrobotsthatrecordnoinformationabouttheirsurroundings,

or it could be as complicated as developing a national or international code for robot

capabilities somewhat like the widely used United States road symbols.257A suitable

pictogram‐basedmarking strategy could, in the best case, convey important information

quickly,butislikelytobeeffectiveonlyinsomescenarioswhileineffectiveinothers.

The fuselage‐marking option has the great disadvantage of being of little value at night.

Markingsonmostdrones,nottomentiontheonthesmallerones,wouldbehardtodiscern

once the drones achieved any substantial altitude. On the other hand, markings might

workbetterforland‐basedrobots,andcouldworkparticularlywellforrobotsthatwould

beusedinsituationswherepeoplewouldbelikelytoencounterthemrepeatedly,suchasa

householdorofficerobot.

b. ExPostNotice:RobotIdentification

When,byaccidentorplan,arobothasharmedapersonorproperty,thevictimwill

needaway to trace the robot to theparty responsible for thedamages.258For remotely

255Battery‐powered tags typically have a read range of 300 feet (100meters). RFIDFrequently Asked Question, How much do RFID readers cost today?, RFID Journal,http://www.rfidjournal.com/faq/show?139.

256RFID Frequently Asked Question, RFID Journal, How much do RFID readers costtoday?,http://www.rfidjournal.com/faq/show?86.

257Fora listseeU.S.Dept.ofTransportation,FederalHighwayAdministration,ManualonUniformTrafficControlDevices(MUTCD)(2009MUTCDwithRevisionNumbers1and2incorporated, dated May 2012), http://mutcd.fhwa.dot.gov/kno_2009r1r2.htm; see alsoU.S. Dept. of Transportation, Federal Highway Administration, National Standards forTraffic Control Devices; the Manual on Uniform Traffic Control Devices for Streets andHighways;Revision, 74 Fed.Reg. 66720 (Dec. 16, 2009) (describing changes fromearlieredition),http://edocket.access.gpo.gov/2009/pdf/E9‐28322.pdf.

258See,e.g.,Act of Jul. 29, 2013, ch. 686, 2013Or. Laws686§15(1) (2013) (requiringtrespassvictimtogivenoticetodroneownerbeforecauseofactionaccrues).


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controlledrobotstheresponsiblepartywillusuallybetherobot’soperatorortherobot’s

owner. Other scenarios are possible. For example, if the injury was due to a design or

manufacturingdefectinamass‐producedrobot,thenunderbasicproductliabilityrulesthe

manufacturer and sellerwill be liable aswell in addition to the owner. If the robot has

indiciaofmanufacture,asdoesamoderncarorboat,thatwillsufficetotracearesponsible

party. Eveninthiscase,however,thethird‐partyvictimwouldstillbeentitledtosuethe

owneroroperatorwhowouldthenhavetosuethemanufacturerorseller. Therewillbe

fewifanyrobotharmscenarios,however, inwhichthevictimwouldhavenoclaimatall

againsteithertheowneroroperatorexcept forthose(1)wheretherobotwasblameless

andtheharmwasinfactcausedbysomethirdparty,e.g.,someonewhopushedtherobot

ontothevictim,or(2)somethirdpartyinterferedwithortookcontroloftherobotandthe

owner or operatorwas blameless for failing to prevent it, or (3) the owner or operator

herselfwasthevictim.

Forautonomousrobotstheresponsiblepartywillinthemostcommoncasesbethe

owner. Thereare,however,esotericpossibilities thatgobeyondthescopeof thispaper.

Forexample,imagineagardeningrobotwithsignificantautonomyandcapableoflearning

fromexperience. Imagine furtherthat therobotowner’sneighborhasbeenteaching the

robot stupid robot trickswhile the owner is atwork. In the course of demonstrating a

stupid robot trickwhile both the owner and the neighbor are away the robot injures a

workerwho has come to deliver something. Depending on the facts, and depending on

one’stheoriesofresponsibilityanddeterrence,onemightassignresponsibilityforthistort

to the neighbor, the owner, the robot’s programmer, the robot’s designer, and/or the

robot’smanufacturer.259

Setting up a licensing regime and national or state‐based registries would help

connectamalfeasantrobottoitsowneroruser,butnosinglesystemislikelytoworkinall

circumstances. Because drones can be small and may be used outdoors in low‐light

situations, license plates or airplane‐style markings alone may be poor solutions;

conversely, licenseplates ormarkings shouldworkwell for larger andpurely terrestrial

259Scenarioslikethismakeonedoubtprojectionsaboutthefutureshortfallsinlawyeremploymentatleastuntilrobotsthemselvescandothework.


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robots.TheRFIDandtransponderregimesdiscussedabove,260requiredetectiongearand

maynotbeeffectiveiftherobotdoesnotremainatthesceneoftheinjury.

Even if they are not always visible, giving flight‐capable robots an equivalent to

aircraft tail markings would at least provide some means of connecting robots to

responsibleparties.Land‐basedrobots,andperhapsairborneonesalso,couldberequired

tocarryastandardizedinternalmarkingequivalenttotheVehicleIdentificationNumbers

(VINs).TheNationalHighwayTrafficSafetyAdministration(NHTSA)hasrequiredthatall

cars sold in theUS sincemodel year 1981 carry a 17‐character VIN,261and the rule has

sincebeenextendedtoothervehiclesandcertaincarparts.262

RequiringtheequivalentofVINsonmobilerobotsandcreatinganowner’sregistry

wouldnotonlyhelpidentifytheresponsiblepartyinthecaseofrobottortsbutwouldhave

the side‐benefits of helpingdeter robot thefts andofmaking it easier to reunite owners

withstolenrobotsaftertheywererecovered.Interestingly,inNHTSA'sauthoritytoissuea

safety standard requiring standardized VINs has been upheld on the grounds the

requirementcontributedtovehiclesafety(indirectly)byreducingerrorsincompilingdata

onmotorvehiclecrashesthatcouldbeusedtounderstandsafetyproblems,supportfuture

standards,andhelptracestolenvehicles.263

260Seesupratextaccompanyingnotes250‐255.261Seegenerally National Highway Traffic Safety Administration, Vehicle Identification

Numbers (VINs), http://www.nhtsa.gov/Vehicle+Safety/Vehicle‐Related+Theft/Vehicle+Identification+Numbers+%28VINs%29.TheNationalMotorVehicleTitleInformationSystem,operatingundertheauthorityof

the U.S. Department of Justice by the American Association of Motor VehicleAdministrators,maintainsandtracksmotorvehicletitlehistories.See49U.S.C.§§30502,30503(2012).

262NationalHighwayTrafficSafetyAdministration,supranote261.263SeeVehicleEquip.SafetyComm'nv.NHTSA,611F.2d53,54(4thCir.1979);seealso

NewYorkv.Class,475U.S.106,111‐12(1986)(discussingadvantagesofVINs includingreducingnumberofpeoplenotcompensatedforaccidents,workingwithstateregistrationand safety requirements, and concluding that because VINs help identify stolen autos,whicharedisproportionatelyinvolvedaccidents,“theVINsafeguardsnotonlypropertybutalsolifeandlimb”).


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3. Recommendation:AMixedApproach

In lightof these considerations,we suggest amixedapproach inwhichallmobile

robots264wouldberequiredtocarrywarningmarkings,lights,andtheequivalentofaVIN

thatwouldberecordedinastateornationalregistry.Inaddition,allaerialrobotswould

be required to carry an activeRFID chipwith themaximumpracticable range given the

stateofRFID technology. Therangerequiredcouldbeadjustedannually fornewrobots

basedonimprovementsinRFIDtechnologyuntiltherangeslightlyexceededtheminimum

heightrequirementestablishedfordrones.

No discussion of a notice regimewould be complete without some discussion of

cheating.Noticeregimesareineffectivewhenthereareasufficientnumberofbadactors.

Inaworldwithwidespreadcheating,noticeisnotreliable,soitbecomesmorereasonable

to lookatalldronesaspotentialthreats. Evenarelativelysmallnumberofbadactors—

liars—canundermineanoticeregimeiftheycausedangerousfalsereliance.Enforcement

ofdisclosurerulesforrobotsingeneral,anddronesinparticular,willbedifficult,butcivil

andevencriminalpenaltiesforfalsestatementsmaybeinorder.Werewetotransitionto

alegalregimeinwhichthedefaultruleprivilegedreasonableself‐defense,buttheowner‐

operator’s standardized and intelligible declaration of harmlessness made self‐defense

presumptivelyunreasonable,thenafalsestatementofharmlessnessshouldbeconsidered

fraudorworse.Weproposethatthepenaltyformis‐identifyingarobotbecomparableto

that for falsifying or obscuring a license plate,265and that the penalty for falsifying or

altering a robot’s internal unique identification number be equivalent to the penalty for

alteringaVIN.266

264Onecould limit it tomobilerobots thatoperatedoutside theowner’sproperty,butthatwouldfailtocoverthecasesofrobotsoperatingonpropertieswheretradespeopleandmembersofthepublicmightbeinvitedtoenter.

265See,e.g.,CAL.VEH.CODE§20(West,WestlawthroughCh.3of2014Reg.Sess.)(makingitacrimetomakeafalsestatementinapplyingforalicenseplate).

266See, e.g., 18 U.S.C. § 2321 (2012) (“Whoever buys, receives, possesses, or obtainscontrolof,withintenttosellorotherwisedisposeof,amotorvehicleormotorvehiclepart,knowing thatan identificationnumber forsuchmotorvehicleorparthasbeenremoved,obliterated, tampered with, or altered, shall be fined under this title or imprisoned notmorethantenyears,orboth.”).


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V. RobotRightsAgainstPeople

Peoplehavesignificantrightsandprivilegespermittingthemtodefendthemselves

againstvariouspossiblephysical,property,andprivacyharmsthatmightbecommittedby

robots.Theserights,however,arenotunlimited.Theexistenceoflimitsonhumanrights

toself‐defensetellsthattheremustbecaseswhere,ineffect,therobotshavearightnotto

be harmed. Wehasten to add that today “robot rights” can onlybe a shorthand for the

rightsoftherobots’ownersortheowner’sagents.Inlaw,atpresent,arobothasthesame

rightsasasock. Perhapssomedayrobotswillachieveorsimulatesentiencetothepoint

wheresocietyrecognizesthemas legitimateholdersofsomebundleofrights,be it those

held by animals, or citizens, or something in between. At present, however, the idea of

“robotrights”isinfactonlyaproxyfor“robot‐owner’srights.”

Evenso,we candeduce somecorrelatives267from thedescriptionofwhenpeople

areprivileged to fightbackandwhen theyarenot. InHohfeldian terms,when the state

createsarightforoneperson,itcreatesacorrespondingdutytorespectthatrightonone

ormoreothers.268Similarly,ifthestategivesapersonaprivilegetoact,itdisablesothers

frommakinglegalcomplaintsifthatprivilegeisexercised.269Wehaveseenthataperson

hasaprivilege toself‐defenseagainstrobots if therobotattacksheror if shereasonably

believes the robot is about toharmher; the sameholds true for threats to thirdparties.

267See Wesley Newcomb Hohfeld, Some FundamentalLegalConceptions asApplied inJudicialReasoning,23YALEL.J.16(1913).

268“Legalrights,accordingtoHohfeld,arenotmerelyadvantagesconferredbythestateon individuals. Any time the state confers an advantage on some citizen, it necessarilysimultaneously creates a vulnerability on the part of others. Legal rights are not simplyentitlements,butjuralrelations.Correlativesexpressasinglelegalrelationfromthepointofviewofthetwoparties.‘[I]fXhasarightagainstYthatheshallstayofftheformer'sland,thecorrelative(andequivalent) is thatY isunderaduty towardX tostayoff theplace.’“JosephWilliamSinger,TheLegalRightsDebateinAnalyticalJurisprudencefromBenthamtoHohfeld,1982WISC.L.REV.975,987.

269“[P]rivilegesarethecorrelativesofno‐rights. ‘WhereasXhasarightorclaim thatY,theotherman,shouldstayofftheland,hehimselfhastheprivilegeofenteringontheland;orinequivalentwords,Xdoesnothaveadutytostayoff.’IfAhasnodutytowardB,AhasaprivilegetoactandBhasnorightagainstA.Thus,ifAhastheprivilegetodocertainactsorto refrain from doing those acts, B is vulnerable to the effects of A's actions. B cannotsummontheaidofthestatetopreventAfromactinginsuchamannernomatterhowA'sactionsaffectB'sinterests.”Id.


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Theonly limitonthisprivilege isthatthebeliefmustbeobjectivelyreasonable, inthata

judgeorjurywouldfindthatanordinaryreasonablepersoncouldhavebelieveditunder

thecircumstances. Thus, thecorrelativerightofa robot—recall, this is shorthand—is to

notbeinjuredbypersonswhounreasonablybelievetherobotisdangerous.

Regardingthreatstoanddamagetoproperty, thecalculationismorecomplicated.

People have a privilege to damage a robot to protect property, but only so long as the

propertybeingprotectedreasonablyseemsmorevaluablethantherobot,subjectalwaysto

thereasonableimperfectionsofthevictim’sabilitytodiscerntherelativevalues.Thus,the

robot’srightistonotbedamagedinordertosaveclearlylessvaluableproperty.

Privacy ismore complicated still. First, althoughwe suggest that intrusion upon

seclusionshouldgive rise toaprivilegeof self‐help, thequestion isnot freeofalldoubt.

Assumingthere isaself‐helpprivilege, therearestill the twinproblemsofvaluationand

detection.Notonlyarerobotshardtovalue,butsotooaremanyformsofprivacy.Worse,

atpresent it isnearly impossible for thereasonableaveragepersontotell ifarobot that

entersherpropertyiscollectingimagesorseekinglocalwi‐fiorotherdata,orifitmightbe

abouttodoso.Ifitisreallythecasethatareasonablepersonwillbejustifiedinsuspecting

any robot that is hovering nearby (or,maybe that has been hovering for some time) of

seekingtoinvadeherprivacy,thentheconclusionisthattrespassingrobotshavenorights

at all until and unless they do something to demonstrate that they are not a threat to

privacy.

Finally,wenotethatevenwhenarobotisunjustlyattackedbyaperson,therobot

hasnoprivilege,muchlessaright,toharmapersoninitsowndefense.Inthissense,Isaac

Asimovpredictedatleastonelawofroboticscompletelyaccurately.

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