Exactly. In my experience, it's very irregularly enforced. If you're a longtime resident whose car they recognize, the parking cops will rarely if ever ticket you. After a snow emergency last year, a car with a local resident permit parked on my street, barely overlapping my driveway. I filed tickets with 311 after the car hadn't been moved for two days; traffic cops came out, gave it a 'warning' ticket, and then a 'real' ticket a day later. But then they'll ticket other cars like the one above right after 48 hrs have passed.