Privacy isn't a one-size-fits-all type of thing. I think there is an inherit difference between reading license plates that are publicly visible on the roadway

Privacy isn't a one-size-fits-all type of thing. I think there is an inherit difference between reading license plates that are publicly visible on the roadway versus tracking license plates over time and storing that data for a long enough period that someone can deduce even more personal information from it. If you were to say "is it okay to read license plates and check a stolen vehicle registry" I don't think many people would complain. But if you were to ask, "Is it okay that i know where you live and work and hang out on a regular basis by just reading your license plate," that's a different story. If they just erased the data after a few days that would take care of most privacy concerns that people have.