A U.S. federal court has held that geofence warrants are unconstitutional under the Fourth Amendment, finding that they fit the definition of general warrants that are “categorically prohibited” by that Amendment. EFF, TechCrunch. Geofence warrants, you may recall, require a data provider (usually Google) to identify all users in a given area during a given time period. While ruling them unconstitutional, the U.S. Fifth Circuit Court of Appeal nonetheless allowed evidence collected under a geofence warrant in the case under consideration, citing the good-faith exception, given the novelty of such warrants at the time and the lack of legal guidance available to law enforcement: see the court’s decision.

Geofence warrants are now in something of a grey area: the Fourth Circuit upheld geofence warrants’ legality, at least under certain circumstances, only last month. The two cases may not be an apples-to-apples comparison, but even so the constitutionality of location data searches may take a while (and the Supreme Court, eventually) to sort out.