Two, they're pointed exclusively at roads.
Three, their outputs don't show up in court cases as evidence, which itself dramatically reduces the danger (even if they potentially could maybe support parallel construction)
Speed and stop cameras are very very good and should be virtually everywhere with extremely strict control on their outputs.
That's not true - I was recently a juror on a UK trial where we were shown ANPR photography of the defendants' vehicles. Here's some other examples of cases in the UK where the prosecution presented the jury with ANPR evidence:
https://www.casemine.com/judgement/uk/693b0db6b21a3a02e931ce...
https://www.2hb.co.uk/news/class-a-drug-importation-trial-co...
https://www.2br.co.uk/sam-magee-kc-successfully-prosecutes-m...
https://www.svs-solicitors.co.uk/additional-notable-cases-20...
https://www.judiciaryni.uk/files/judiciaryni/decisions/The%2...
ANPR networks are obviously created specifically for surveillance.
GP said "I remember pushback to automated speed cameras" and I said sure, but that was still very different because they weren't part of a surveillance network. Your proof that ANPRs are used for surveillance illustrates the same difference I am pointing out.
Then the gap between UK's government-owned ANPRs and the privately owned Flock cameras is still probably quite large. I don't know the UK's privacy laws, but they probably exist. Flock, as a private party in the US, essentially has zero controls whatsoever on how the data is used. Including – most critically – that the government can simply buy the data from Flock (sans warrant) that would be illegal for the government to produce itself.
In any case, an evidence modality that can only be used via parallel construction is still far, far, far less risky than one that can be freely introduced in court.
Now I just struggle to understand the naïveté in general.