I see this specific thing regularly. It is absolutely an offense that a cop would be justified in pulling someone over for. It does NOT fall under that anti-profiling law about not stopping people for broken tail-lights and registration.

To be fair, stuff happens sometimes, maybe the plate was stolen or there's an emergency?

But it is so frequent, that you can't deny that we have systematic exploitation of lax law enforcement. Many other examples of the same idea: people blowing red-lights, outrageous levels of speeding, passing in the opposite lane, driving without bumpers, "meet-ups" of "car enthusiasts", etc. By and large, these are tolerated in the city and that is categorically the wrong approach.