SignalTrace, a system marketed by the security company Leonardo, is designed to work alongside automatic license plate readers. The company says it can recognize groups of consumer devices that regularly move together, then associate them with license plate records and time-stamped locations. The pattern can then be searched even when a police investigator does not know the plate number

I grow weary of this overreach. We really need to randomize device identifiers at just about all levels. Then again, I've always said the identifiers existing in the first place is a desperate bid to try to artificially implement a fingerprint in a society that until recently was seemingly fully cognizant of the folly of trying to do such things, and recognized such attempts for what they are... Power grabs.