The Supreme Court decided two years ago in Carpenter v. United States that the Fourth Amendment requires police to obtain a warrant, in most circumstances, to access GPS location information spanning seven days or more from a cell phone user. Prior to that decision, the court had held that voluntarily providing this information to third parties like technology companies did not have Fourth Amendment protections and thus litigants did not have any reasonable expectation of privacy.
Although the court majority labeled the decision “narrow,” it nonetheless led to questions about where else Fourth Amendment protections might be applied in future decisions related to various forms of technology. Dissenting Justice Samuel Alito predicted the decision “guarantees a blizzard of litigation.”
While Justice Alito was correct that some new cases have come forward, but for the most part lower courts have followed the contours of the Carpenter decision when asked whether users can be granted Fourth Amendment protection for such non-content data as financial and billing records, IP addresses, subscriber records, and lists of devices that accessed a wireless network. Most recently, in June, the First Circuit Court of Appeals overturned a lower court ruling granting Fourth Amendment protection to eight months’ worth of video feed recorded by a pole camera, labeling this a “conventional surveillance technique” and thus not analogous to collection of cell-site location data.
Where lower courts have extended the protections under Carpenter, this has involved cases with very similar information at stake, such as real-time cell-site location (as opposed to past locations), historical information dating back fewer than seven days, and vehicle-based GPS location data obtained through a third party.
There have been a few other individual cases with very particular circumstances where lower courts have expanded Fourth Amendment protections via Carpenter, including one case in the Fourth Circuit regarding extensive monitoring of a defendant’s computer, and an Ohio case that involved medical records with information about alcohol or drug use.
In other instances, courts have declined to extend Fourth Amendment protection but hinted that they might in the future as technology progresses. For example, the U.S. District Court for the Northern District of Indiana ruled in June that registration information and records of usage for Facebook subscribers did not fall under Carpenter but stated that “one day” social networks might become as “indispensable” as cell phones and thus deserve similar protection.
In another recent case, the Supreme Judicial Court of Massachusetts ruled that a defendant was not protected against having their data collected from Advanced License Plate Readers located at four fixed spots on public roads. But the court said that if such information was sought more widely, to the point where police could virtually track someone’s every move, this would make these license plate readers “the vehicular equivalent of a cell phone ‘ping.’ ”
As with all areas of jurisprudence, case law derived from Carpenter no doubt will continue to develop over time, and you will be able to learn all about it on your cell phone.