It has been stated that these cameras are legal because "you have no expectation of privacy in public." Is this true?
Courts have found that individual pictures are constitutional; however long-term tracking, data collection, and data analysis of your data is illegal. Long-term tracking isn't just "being seen" - it's an imposed, automated dragnet and stalking. Courts recognize the "mosaic theory": individual public moments, when stitched together 24/7, reveal your doctor visits, political rallies, and entire daily life without your consent or a warrant. It's not the same as someone watching you pass by. See United States v. Jones, Carpenter v. United States, and Katz v. United States.
Your phone spies on you already. Why worry?
This is pure defeatism that ignores personal agency. You can buy a Faraday bag, De-Google your phone, not have one at all, or choose to leave it at home entirely - you have consumer choice. You can’t opt out, alter, or opt out of a state monitored network of automated license plate readers scanning every public road.
What about crime and terrible things that criminals do? If your kid was abducted, wouldn't you’d want universal surveillance?
When you resort to absurd emotional traps and logical fallacies (Appeal to Emotion, False Dilemma, Faulty Generalization), it's a confession you can't defend the tech on its merits. Police have solved crimes for generations without violating constitutional rights, and extreme edge cases don't justify permanent dragnet surveillance of the entire population.
Is there any way to tell if my data has been collected? Is there any way to tell if my data has been queried?
If you travel around at all, your data has been collected by a Flock camera. At this time, there is no way to tell if your data is being held or to determine all the places where your data is kept. You may be able to tell if your data or license plate has been subject to a query at HaveIBeenFlocked.com. Note that this data is only limited to publicly available data. You can try an OPRA request to the appropriate authority (or authorities) asking for this information.