A few years ago I was living in San Diego county and thought my car was stolen. Called the police and when the officer showed up he said “let me put your plates into our system to see if any of our license plate readers picked it up”
I asked him where the readers were, thinking there were maybe a handful around the county. He responded by saying “oh they’re everywhere, if your car went half a mile from your house we will have it scanned”. He did all this directly in his patrol car without any sort of obvious oversight. When I glanced at the screen it showed EVERYWHERE I had driven in the past month.
It was quite shocking from a privacy perspective to realize this