The wardens seem to be on 24 hour patrol 7 days a week. Go visit someone for an hour at 10 pm on a Sunday night in a residents parking zone, and bang you get a ticket – even though there are dozens of empty parks.
Park on a bus stop on a day there are no buses usin that stop , and wham got you.
They also ticket you if the warrant has expired. That money goes to central Government, but I wonder what sort of commission they get from the $200 for doing the ticketing?