And how do they automatically detect the criminal wrongdoing being committed by that car or its occupants? That is the part I don't get. Yes if they decide to look for John Smith, License plate 1AMJ0HN, then they can probably automatically find his car in that footage, and they can watch that footage to see what he was up to. But watching that footage and figuring out if he did anything they can prosecute him for is not a simple task for any computer algorithm I can think of, and would require time to do manually. And with out doing it in an automated manner they can't possibly do this for 'everyone' which means they have to have reason to already suspect the people they do choose.

I see absolutely no way that bringing up the existence of license plate scanners created a situation where there was no slippery slope.

Also the recorded video collection grows to be a ridiculously large amount of data over time, even detecting all video of John Smith's car across the United States will become an expensive task to complete computationally. And for everyone? Well even more expensive.

Add on the concept that camera's will not be covering all of the United States at times, and if you are just using make, model, and color of cars to track people between license plate readers shell games where similar cars rearrange them selves in tunnels or garages will become extremely effective at defeating surveillance if license plate readers are not basically everywhere.

So in spite of you deciding to bring up license plate readers, and explain how they can be used to assist in tracking with airborne surveillance I still fail to see the relevance of how they ensure that 'everyone' will be monitored.