Technology October 2021

Reasonable Expectation of Privacy

Drone surveillance Requires a warrant

Written by Pierre Grosdidier

Long Lake Township in Michigan used a drone to confirm that Todd Maxon operated an illegal junkyard on his property, which was hidden from view from the roadside.1 The township sued Maxon, who argued that the unauthorized flights amounted to an illegal search in violation of the Fourth Amendment. The trial court denied Maxon’s motion to suppress the drone photo evidence but the Michigan Court of Appeals reversed. The case is important because it differentiates low-altitude drone flights from aircraft overflights in the navigable airspace, which the U.S. Supreme Court has long held are legal.

The Fourth Amendment protects persons from unreasonable searches. The search of a home and its curtilage, its immediate surrounding, requires a warrant supported by probable cause, with exceptions.2 A Fourth Amendment search also occurs when authorities intrude on a person’s subjective expectation of privacy that society recognizes as reasonable. In analyzing the person’s expectation, the court must consider “the totality of the circumstances surrounding the intrusion.”3 For example, a person in a phone booth can reasonably expect to conduct a phone conversation without being recorded unless the police have a search warrant.4 But, what a person knowingly exposes to the public enjoys no such protection.5 Thus, the police’s plain visual observation of a house from a public thoroughfare is not a search.

Maxon argued that the drone pictures violated his subjective reasonable expectation of privacy and that the drone’s flight violated Federal Aviation Administration regulations. In technologydenying Maxon’s motion to suppress, the trial court relied on Florida v. Riley, a U.S. Supreme Court case that held landowners do not have a reasonable expectation of privacy from police helicopter overflights 400 feet above their property.6 Riley holds that the Fourth Amendment does not bar the police from observing the inside of a greenhouse from a public vantage point where they have a right to be, be it from an aircraft in the navigable airspace.

The court of appeals first reiterated that a person’s reasonable expectation of privacy is not a moving target that recedes with improving surveillance technology.7 The court also drew on Riley and its dissenting opinions to reject Maxon’s argument that noncompliance with FAA regulations was tantamount to a violation of the Fourth Amendment.8 What counts “is not whether the police were where they had a right to be under FAA regulations,” but whether a person’s expectation of privacy was “rendered illusory” by possible public observation from aerial traffic in the navigable airspace. The U.S. Supreme Court confirmed in Riley that such expectation was illusory because these overflights were nonintrusive and anyone flying a plane could look down and see what the police saw inside the greenhouse.9

In this case the court held that “low-altitude, unmanned, specifically-targeted drone surveillance of a private individual’s property is qualitatively different from the kinds of human-operated overflights permitted by Ciraolo and Riley.”10 It held that such flights encroached on a person’s reasonable expectation of privacy and, therefore, required a Fourth Amendment search warrant, or an exception thereto such as consent.11 Drones, the court reasoned, are more intrusive than airplane overflights; they are less frequent, inadvertent, and costly, and inherently much easier to deploy. Moreover, drones’ agility, speed, and stealth drastically expand their surveillance abilities “not just in degree, but in kind.” Significantly, the court saw “little meaningful distinction” in this case between drone flights just inside and outside a property line.12 The key issue remained a person’s reasonable expectation of privacy, which included the expectation that a drone overflight would be exceptional and trespassory, regardless of whether the drone flew at 300 feet or directly against a bathroom window. TBJ

This article, which first appeared in Circuits, has been edited and reprinted with permission.

1. Long Lake Twp. v. Maxon, No. 349230, — N.W.2d —, 2021 WL 1047366, at *1 (Mich. Ct. App. Mar. 18, 2021). A private subcontractor performed the drone flights acting for the township. Id. at *3.
2. Id. at *3.
3. Id.
4. Katz v. U.S., 389 U.S. 347 (1967).
5. Maxon, 2021 WL 1047366, at *3.
6. Id. at *2 (citing Florida v. Riley, 488 U.S. 445 (1989)).
7. Id. at *4 (citing Carpenter v. U.S., 138 S. Ct. 2206, 2217–19 (2018); Kyllo v. U.S., 533 U.S. 27, 33–35 (2001)).
8. Maxon, 2021 WL 1047366, at *6 (citing Riley, 488 U.S. at 464–65).
9. Id. at **4–5 (citing Calif. v. Ciraolo, 476 U.S. 207, 212–15 (1986).
10. Id. at *6.
11. Id. and n.4.
12. Id. at *7.


Headshot of Brad JohnsonPIERRE GROSDIDIER is an attorney in Houston. He belongs to the first group of attorneys certified in construction law by the Texas Board of Legal Specialization in 2017. Grosdidier’s practice also includes data privacy and unauthorized computer access issues and litigation. Prior to practicing law, he worked in the process control industry. Grosdidier holds a Ph.D. from Caltech and a J.D. from the University of Texas. He is a member of the State Bar of Texas, an AAA Panelist, a registered P.E. in Texas (inactive), a member of the Texas Bar Foundation, a Fellow of the American Bar Foundation, and the State Bar of Texas Computer & Technology Section chair-elect for 2021-2022.


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