"An armed robber walks into seven stores in Indiana and Michigan during a three-week crime spree in October 2017. Investigators get from the robber's phone carrier real-time cell site location information (CSLI) that show his phone's pings to nearby cell towers which help the investigators geolocate their suspect. The robber gets arrested and charged in federal court with five counts of robbery and several accompanying weapons charges. And the rest of the world gets an opinion from the US Court of Appeals for the Seventh Circuit on one of the many questions that the Supreme Court left open when it decided its seminal privacy-related opinion Carpenter v. United States 138 S. Ct. 2206 (2018)."