Supreme Court grapples with limits to 'geofence warrants' over privacy concerns
The Supreme Court on Monday grappled with whether to impose limits on when and how law enforcement uses so-called “geofence warrants" to track down a criminal suspect using cellphone location data from a broad swath of users, including people with no connection to a crime.
During oral arguments in a landmark case from Virginia, many justices appeared sympathetic to government arguments that digital dragnets are a critical tool for solving crimes despite concerns they inherently violate Americans' right to privacy.
"If you don’t want the government to have your location history, you just flip that off," Chief Justice John Roberts noted, referring to common privacy settings on most phones. "If you don't want them to peer into your window, you close the window or your shades."
Geofence warrants compel service providers, such as Google or Verizon, to turn over location history and time stamps from all cellphones within a specified area over a specified timeframe. A single warrant can yield data on a large number of individuals, often without their knowledge.
Normally authorities ask a judge for a warrant with specific request on a specific individual or organization.
Defenders of the practice insist access to the information is fair game. Critics say the warrants constitute an unreasonable search forbidden by the Fourth Amendment.
"I think one should be permitted to hand over data to a third party without assuming the government is going to look at it," argued attorney Adam Unikowsky, representing a bank robber challenging his conviction over prosecutors' use of the data.
Okello Chatrie, the petitioner in the case, was indicted on charges related to an armed robbery of a Virginia credit union in 2019 and wants key cellphone location evidence against him thrown out.
Authorities relied heavily on data obtained from Google under a geofence warrant that placed Chatrie's cellphone within 150 meters of the bank during the crime. Chatrie entered a provisional guilty plea but has reserved the right to seek to toss out the evidence on appeal if the court rules in his favor.
The Trump administration, which is defending Chatrie's prosecution, argues that by sharing location information with apps and service providers like Google, a person forfeits any expectation of privacy.
Most telecom providers stipulate in the fine print of customer contracts that certain data stored in the cloud is not entirely private and may be turned over to law enforcement if ordered by a court. Individuals can turn off location sharing on their device to ensure privacy, but many people do not.
"He voluntarily disclosed to Google the information about where he was going to be," Justice Samuel Alito said of Chatrie. "He not only turned [location data] on, but had he read his contract with Google, he could see that Google retained the right to turn this information over to law enforcement."
Several justices, however, expressed significant concerns about geofence warrants being too broad, suggesting the court could consider imposing some limits on the tool going forward.
"It would also affect Google Photos … Google Documents … Google Calendar, your entire calendar," noted Justice Sonia Sotomayor. "If this is consent, that means the government can seek those documents for any reason, not just the commission of a crime, or no reason, correct?"
"Correct," said Unikowsky.
Justice Amy Coney Barrett said she was "struggling" with the case and what constitutes a reasonable expectation of privacy in the cellphone age.
"You really are saying that you could track someone going inside a home … about movements inside a home, movements to the bathroom, movements to the bedroom, all of that, if the confidence interval is narrow enough?" Barrett asked deputy solicitor general Eric Feigin skeptically.
"I do think we could have done that here because of the warrant," Feigin replied.
Justice Brett Kavanaugh, often a key vote in close cases, suggested that the dispute boils down to just how narrowly tailored a geofence warrant is -- and that some guidance to judges may be required.
"It seems to me, we should set some parameters, reasonable -- temporal scope, reasonable geographic scope, but then we trust issuing magistrates around the country to implement those rules," he said.
Geofence warrants have become increasingly valuable to investigators in tracking down criminal suspects, missing children and hikers lost in the wilderness. A decision limiting their use could hamper law enforcement efforts in the future, experts say.
For generations, cops have obtained warrants to lawfully seek information from a specific suspect in a crime. But "geofence warrants" can do the reverse -- scanning cellphone data of thousands of innocent individuals in hopes of finding a suspect to apprehend.
Google received 9,000 warrants in 2019 alone seeking cellphone location data information, Unikowsky said.
“All of these warrants are sealed,” he said, urging the court to impose some first-ever limits on the practice. "The reason the [public] outcry doesn't exist is that no one knows that thousands of times per year their accounts are being searched."
A decision in the case is expected by the end of June.
