I never hear that question from Flock supporters. The question I hear[†] is "why shouldn't we be pulling over stolen cars?". It's a much harder one to answer than the straw man questions we set up for these things.

(To be clear: I think the current generation of ALPRs is a policy failure and that major changes need to happen inside state law enforcement systems before they can be deployed successfully. But I also think people on HN have a real problem in convincing themselves about the obvious righteousness of their anti-surveillance arguments.)

[†] I heard arguments like these because I was deeply involved in getting the cameras disabled in the inner-ring Chicago suburb in which I live, getting the first ACLU CCOPS ordinance in Illinois passed there, and helping draft what are probably the most detailed ALPR police General Orders in any municipality, or at least were at the time. Which is a long and pretentious way of saying I spent a lot of time talking to people who are not Very Online.