Why aren't these cars/bikes fined while parked on the street?

I, too, would love to know the answer to that question. I've been seeing them all over in NY, where I understand they're illegal, and have no idea how they're not cop magnets.

Back in the day, I lived on a dirt road, and I never washed my car. So the tag was a little hard to read. But hey, there was nothing obviously intentional about it.