Most are targeted ALPR camera systems that take pictures of license plates, check the plates against local hot lists, and then flush the data if there’s no hit.

Flock is building a giant camera network that records people’s comings and goings across the nation and maintains those records despite any link to crime for an indeterminate amount of time.

The other players like Axon and Motorola are looking to follow Flock's lead, but mass surveillance is the main problem.

I think Flock might be a "limited hangout" to distract from much more powerful surveillance technology.

There have been systems designed & deployed that make ALPRs look like kittens.

https://en.wikipedia.org/wiki/ARGUS-IS

Don't touch Americans' cars. Notice how more people die from cars than guns and there's no outcry.

Trends are random. This one has a large underlying informed group, deflock, centered in a Discord server. It then became common internet opinion to be opposed to it.