How about a law that says your documents, like your car registration number on a plate, doesn't have to be displayed except in case of reasonable articulable suspicion a crime has been committed. We could call it, the 4th amendment.
I’ll throw you an olive branch and say the registration sticker is completely pointless. The source of truth for whether my car is registered is in a database, not on a sticker. Someone can steal your sticker which results in a false positive for the thief and a false negative (and huge headache) for the victim.
Your plate is displayed because driving is a privilege, not a right (note that traveling is a right, but you can travel without driving).
So your plate is really the proof that you've paid a bit for the infrastructure to drive on.
It's like having a wrist band to an event. You're not required to attend the event, but if you do attend it, you're required to wear the wrist band.
They will find something else to track you by. I think the idea of no expectation of privacy in public doesn't work anymore with the available tech.