> investigation and possible arrest, people who's only documented action was "being somewhere."

In the example above, the police wouldn't arrest every single person who entered and exited the parking lot. They'd arrest the person who walked out of the lot with your stolen luggage.

> Oh, and while your example is "committed a crime", that same network could easily be used to identity and track people who were, say, coming and going from protests

Again realize that this is legal right? https://www.nytimes.com/2017/08/14/us/charlottesville-doxxin...

There's no right to have your public demonstrations off limits for recording. The whole point of a protest is to be seen. If someone is concerned that they will be associated with some group or cause because of their decision to protest, then they seem to have a fundamental misunderstanding of what a protest is.

> Or voting

You realize the government already has that information? Voters literally filled out ballots and delivered it to the government. They don't need a camera to know who voted, they have the ballots.