Parking at my then girlfriend's condo. They'd changed the parking regulations, sent notices to all the residents (multiple times) and posted the new rules on a board by the front door. I was well aware of them. Couple months in I went over there and couldn't park in the visitor parking (full of resident cars which was supposed to be against the regs, but unsurprisingly they never got towed for that) so I parked in an unmarked but still resident-only space, directly in front of a sign explaining the OLD regulations, which would have made it a legal space.

Of course I got towed, and when I complained they only thing that happened was that they removed the sign the next day. I was still out my $$$.