We mostly agree.

I'd be happy to compromise a bit on point 1. I could accept a high (20%) false negative rate. If the fine were small enough then I'd be OK with a small number of false positives (as long as they're randomly distributed, not hammering one person who happens to live near a faulty camera).

I wouldn't want to compromise on point 2 or 3, particularly for this example (catching impolite drivers).

But what if the example were about a highly accurate system for detecting kidnappers or people traffickers or something? It seems harder for me to argue against enforcement on the grounds of privacy or slippery slope.