On February 5, 2018, three individuals acting in concert robbed Sylvester Cobbs, a Contract Route Driver with the United States Postal Service. At approximately 5:20 p.m., Cobbs arrived at the Lake Cormorant Post Office. As he normally would, Cobbs backed his mail truck up to the back door. Before Cobbs could open the back door to the post office, however, an unknown assailant—later determined to be Defendant-Appellant Gilbert McThunel—sprayed Cobbs with pepper spray, struck Cobbs multiple times with a handgun, threatened to kill him, and grabbed the registered mail bags from Cobbs’s truck.

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“Unlike a warrant authorizing surveillance of a known suspect, geofencing is a technique law enforcement has increasingly utilized when the crime location is known but the identities of suspects are not.” Thus, geofence warrants effectively “work in reverse” from traditional search warrants. In requesting a geofence warrant, “[l]aw enforcement simply specifies a location and period of time, and, after judicial approval, companies conduct sweeping searches of their location databases and provide a list of cell phones and affiliated users found at or near a specific area during a given timeframe, both defined by law enforcement.”

So far, Google has been the primary recipient of geofence warrants, in large part due to its extensive Location History database, known as the “Sensorvault.” Google collects data from accounts of users who opt in to Google’s Location History service. Location History is disabled by default. “Once a user opts into Location History, Google is always collecting data and storing all of that data in the Sensorvault.” Location History is stored within the Sensorvault for at least eighteen months, but users may also request that the information be deleted themselves.

Moreover, not only is the volume of data comprehensive, so is the quality. “Location History appears to be the most sweeping, granular, and comprehensive tool—to a significant degree—when it comes to collecting and storing location data.” Google refers collectively to this data, regardless of its source, as “Location History.” Location History data allows Google to “potentially locate an individual within about sixty feet or less,” and in certain circumstances, down to three meters.

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The Fourth Amendment guarantees individuals the right “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” The “basic purpose of this Amendment . . . is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” Moreover, the Supreme Court has established that “the Fourth Amendment protects people, not places,” and the Court has “expanded [its] conception of the Amendment to protect certain expectations of privacy as well.” “When an individual ‘seeks to preserve something as private,’ and his expectation of privacy is ‘one that society is prepared to recognize as reasonable,’ [the Court] ha[s] held that official intrusion into that private sphere generally qualifies as a search and requires a warrant supported by probable cause.” Evidence seized in violation of the Constitution is subject to suppression.

The threshold question posed by this case is whether geofencing is a search under the Fourth Amendment. “A Fourth Amendment privacy interest is infringed when the government physically intrudes on a constitutionally protected area or when the government violates a person’s ‘reasonable expectation of privacy.’” To assess whether a “reasonable expectation of privacy” exists, the Supreme Court has applied Justice Harlan’s two-fold approach as explained in his concurrence in Katz v. United States. Specifically, for Fourth Amendment protections to attach to a person’s privacy interest, the person first must “have exhibited an actual (subjective) expectation of privacy.” Second, that expectation must “be one that society is prepared to recognize as ‘reasonable.’”

While it is true that geofences tend to be limited temporally, the potential intrusiveness of even a snapshot of precise location data should not be understated. Such location tracking can easily follow an individual into areas normally considered some of the most private and intimate, particularly residences. Geofence location data is invasive for Fourth Amendment purposes. Of particular concern is the fact that a geofence will retroactively track anyone with Location History enabled, regardless of whether a particular individual is suspicious or moving within an area that is typically granted Fourth Amendment protection. As the Court in Carpenter explained, while cell phone data is held by private corporations, on a practical level, it is unreasonable to think of cell phone users as voluntarily assuming the risk of turning over comprehensive dossiers of their physical movements to third parties. Given the ubiquity—and necessity—in the digital age of entrusting corporations like Google, Microsoft, and Apple with highly sensitive information, the notion that users voluntarily relinquish their right to privacy and “assume the risk” of this information being divulged to law enforcement is dubious.

Users opt in to having their Location History monitored. Indeed, this was the other consideration … that geofencing is not a “search” subject to the Fourth Amendment. But we are not convinced.

As anyone with a smartphone can attest, electronic opt-in processes are hardly informed and, in many instances, may not even be voluntary. Google’s Location History opt-in process is no different. Users are bombarded multiple times with requests to opt in across multiple apps. These requests typically innocuously promise app optimization, rather than reveal the fact that users’ locations will be comprehensively stored in a “Sensorvault,” providing Google the means to access this data and share it with the government. Even Google’s own employees have indicated that deactivating Location History data based on Google’s “limited and partially hidden” warnings is “difficult enough that people won’t figure it out.”

Not to mention, the fact that approximately 592 million people have “opted in” to comprehensive tracking of their locations itself calls into question the “voluntary” nature of this process. In short, “a user simply cannot forfeit the protections of the Fourth Amendment for years of precise location information by selecting ‘YES, I’M IN’ at midnight while setting up Google Assistant, even if some text offered warning along the way.”

To conclude, we hold that law enforcement in this case did conduct a search when it sought Location History data from Google. Given the intrusiveness and ubiquity of Location History data, Smith and McThunel correctly contend that they have a “reasonable expectation of privacy” in their respective data.

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The Fifth Circuit had such a ruling last Friday, United States v. Jamarr Smith. The case creates a split with the Fourth Circuit on one important issue.

Accessing any amount of geofence records is a search under an expansive reading of Carpenter v. United States. That’s the issue that creates the split with the Fourth Circuit in United States v. Chatrie. As I noted just a few weeks ago, Chatrie held that accessing such records is not a search in the first place, at least if the records sought are relatively limited in scale. The Fifth Circuit expressly disagrees.

Warrants have to be particular. … The place to be searched must be specific. Smith rules that the database Google has created, through which Google looks for matches with the data described in the warrant, is simply too vast to search. When Google queries the Sensorvault database, the Fifth Circuit holds that it is scanning through a “place” too large for the Fourth Amendment to permit.

I think the Fifth Circuit’s warrant ruling is wrong—and not just wrong, but basically bananas. The ruling conflicts with the Supreme Court’s precedents on warrant particularity.

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An especially relevant case is United States v. Karo, which considered the Fourth Amendment implications of installing and monitoring a location tracker in physical space. The relevant part of Karo is the Court’s reply to an argument the government made about warrant particularity. The Supreme Court responded by rejecting the premise and explaining how to draft a warrant in such cases to match the Fourth Amendment particularity standard: “It will still be possible to describe the object into which the beeper is to be placed, the circumstances that led agents to wish to install the beeper, and the length of time for which beeper surveillance is requested. In our view, this information will suffice to permit issuance of a warrant authorizing beeper installation and surveillance.” 

It seems to me that this controls Smith, too. The warrant problem in Karo was a lot like the problem in geofence warrant cases. The “place to be searched” is basically everywhere. The search would occur wherever the beeper happened to go. But instead of saying that no warrant could be obtained, the Supreme Court in Karo articulated a way to draft warrants to allow the surveillance. The place to be searched was the object into which the beeper is to be placed, with the particularity being provided by the length of time for which beeper surveillance is requested.

I personally don’t think geofencing is a search in the first place, as I have argued before. But if we are to say that geofencing is a search, it seems to me that the approach from Karo should govern here. Following Karo, the particularity should be provided by a description of the database into which the query is made, combined with the length of time (and amount of geographic space) the warrant covers. We can argue about how long a period is permissible and how big a geographic space is permissible. But the idea that there is a cap on the size of the database seems hard to square with Karo.

Unfortunately, the Fifth Circuit doesn’t discuss Karo, so we don’t know what the panel’s response to it might be.

Part I-III: https://www.ca5.uscourts.gov/opinions/pub/23/23-60321-CR0.pdf

Part IV: https://www.lawfaremedia.org/article/the-fifth-circuit-shuts-down-geofence-warrants-and-maybe-a-lot-more