The only way within the system is I guess the Supreme Court. They have already laid a framework establishing that tracking requires a warrant, even if it's just making the police's job more efficient and it's data they can get from a tail.

If the license plate tracking gets to that point within metropolitan areas (presumably where cameras are most dense) or they start doing it from blimps or whatever, at least there is precedence for striking it.

It's not going to stop the collection but it should at least prevent the data being used against you in court. Of course, parallel construction. Sigh...