Users should be aware that there is no expectation of privacy in their Google location data, which can be obtained by law enforcement through geofence warrants. Only approximately one-third of active Google users have enabled Location History, which constantly tracks and stores a user’s location information. Google has developed a three-step procedure for responding to geofence requests, including reviewing and objecting to requests that are deemed overly broad. The use of geofencing technology does not constitute a search under the Fourth Amendment, as ruled by the US Court of Appeals for the Fourth Circuit in US v. Chatrie.
https://fourthamendment.com/?p=58338