Your location isn't that big a deal. They can easily get that from License Plate Readers. What will be interesting, is if they ever use the data to give you tickets. I know that there was a discussion of a plan to use the New Jersey Turnpike tollbooths/EZ-Pass to judge speed between two points, and mail you a ticket. I don't think it ever made it out of the starting gate.
Tracking plates is a lot more work.
The problem with police is their power asymmetry and potential for abuse. Tools like this increase that. Additionally, they aren't just random people from the public, they're the people that desired to do policing for motivations which may or may not be healthy.