I had a very pleasant experience with "Parking Enforcement" in a commercial district outside of Pittsburgh recently. I had either forgot to put money in the meter or it ran out. Got back to my car to find a ticket. The fine was only a dollar and I think it was voluntary. On the ticket was printed a note explaining that the business community really values people coming to visit and so doesn't want to annoy those people with high parking rates or ticket fines. It was the most pleasant parking ticket experience I could imagine.