In a collaborative effort, Apple and Google have developed an industry-standard detection feature called “Detecting Unwanted Location Trackers” (DULT) for Bluetooth trackers. This standard allows users on iOS and Android devices to be alerted if an unknown Bluetooth tracker is monitoring their location.
The solution would probably just be to dismiss the alert with a response like “I am on a plane, bus boat, etc. I’m traveling with strangers and their stuff”. Then it would temporarily remember all the local devices, and then dump that list after a set period of time.