Courts have been expanding privacy protections for law enforcement access to real-time cell tower data, a trend attorneys say eventually could include other location-based information.

The U.S. Supreme Court ruled in 2018 that government officials must get warrants for historical cell-site location information under the Fourth Amendment. The justices didn’t rule in Carpenter v. United States on whether real-time data deserved the same protection. Several courts have said since that it does.

The decisions “reflect the growing consensus among courts, legislators, and the public that there is simply too much personal information available electronically for the Constitution not to be triggered in the context of government searches and surveillance techniques,” said Joseph Facciponti, a data privacy and cybersecurity attorney at Murphy & McGonigle PC in New York and a former U.S. prosecutor.

Courts also may look to extend similar Fourth Amendment protections to law enforcement access to sensitive data that offers a window into private habits, such as internet protocol addresses and biometric trackers, attorneys say. Courts are likely to continue to limit government access to cell-site location information (CSLI), attorneys say.

Cases involving “smart utility meters, IP addresses, basic subscriber information, cell-site simulator, and real time CSLI” could very well make their way to the higher courts under the right set of facts, Trisha Anderson, a cybersecurity partner at Covington & Burling LLP in Washington, said.

‘Intimate’ Data

Pennsylvania’s Supreme Court ruled in July that law enforcement officials must get a warrant to collect real-time cell-site data. The court said in Commonwealth v. Pacheo that people have a reasonable expectation of privacy in the record of their physical movements in both real time and historic cell site data.

The court pointed to similar decisions by five other state and federal courts, including United States v. Williams, where the U.S. District Court for the Southern District of Georgia ruled in February that Carpenter applies to the collection of real-time cell-site location information.

“In the wake of Carpenter, we found other courts that addressed this question determined that real-time CSLI is subject to the same privacy concerns as historical CSLI,” Judge Deborah Kunselman wrote for the unanimous Pennsylvania court.

The Supreme Court signaled in Carpenter that it would continue to scrutinize law enforcement access to location-tracking data.

Such data “provides an intimate window into a person’s life, revealing not only his particular movements, but through them his familial, political, professional, religious, and sexual associations,” Chief Justice John G. Roberts Jr. wrote for the court.

Law enforcement officials use historical data to place a suspect within a certain distance of a cell tower. They use real-time data to place a suspect near a crime scene in the moment the data was captured.

Roberts left the door open for other courts to rule on whether real-time cell tower data and other emerging tracking technologies also garner Fourth Amendment privacy protections. Although the justices said that only seven days of CSLI requires a warrant, the narrow opinion didn’t give the government the power to “obtain an individual’s historical CSLI free from Fourth Amendment scrutiny,” Roberts wrote in a footnote.

Law enforcement officers and government officials can collect troves of data in the digital realm that would make a search in the physical world seem unreasonable under the Fourth Amendment, privacy attorneys and academics said.

Location information collected with other data “could provide enough detail about a person’s life that the person could reasonably believe this should be private,” Linda Merola, associate professor of criminology, law and society at George Mason University, said.