Metadata isn’t considered “data” by anti-surveillance law, so analysis of where you go and when is fair game. Thing is, where you go and when can pick you out of a crowd almost instantly.
This extraordinary article at the CATO Institute bears mirroring. Have you seen the customer number on your drivers’ license? Since when are citizens “customers”? Answer – it’s been a while, it’s been right under our nose, and it’s much more widespread than we even dreamed.
Used to be if law enforcement wanted to fingerprint you it took some effort – now they can do it with a smartphone. We’ve moved past national / citizen ID’s to biometrics on the street.