Civil liberties advocates have long argued that “geofence” search warrants are unconstitutional for their ability to ensnare entirely innocent people who were nearby at the time a crime was committed. But errors in the geofence warrant applications that go before a judge can violate the privacy of vastly more people — in one case almost two miles away. Attorneys at the ACLU of Northern California found what they called an “alarming error” in a geofence warrant application that “resulted in a war...