> I feel that's like saying there's "nuance" when the police choose to pull someone over because--unlike the other car--they didn't have a "I Donated To Cops" license plate.

That's not unusual at all. Here is New York parking enforcement ticketing cars who are not participating in a specific activity, while disregarding other double-parked cars that are participating. He even explicitly states that the policy is to allow double parked cars, so long as the driver participates in the desired activity:

https://m.youtube.com/shorts/J7yJfhsuJls