A US federal appeals court ruled last week that so-called geofence warrants violate the Fourth Amendment's protections against unreasonable searches and seizures. Geofence warrants allow police to demand that companies such as Google turn over a list of every device that appeared at a certain location at a certain time. The US Fifth Circuit Court of Appeals ruled on August 9 that geofence warrants are "categorically prohibited by the Fourth Amendment" because "they never include a specific user to be identified, only a temporal and geographic location where any given user may turn up post-search." In other words, they're the unconstitutional fishing expedition that privacy and civil liberties advocates have long asserted they are. Google ... is the most frequent target of geofence warrants, vowed late last year that it was changing how it stores location data in such a way that geofence warrants may no longer return the data they once did. Legally, however, the issue is far from settled: The Fifth Circuit decision applies only to law enforcement activity in Louisiana, Mississippi, and Texas. Plus, because of weak US privacy laws, police can simply purchase the data and skip the pesky warrant process altogether. As for the appellants in the case heard by the Fifth Circuit, well, they're no better off: The court found that the police used the geofence warrant in "good faith" when it was issued in 2018, so they can still use the evidence they obtained.