Met some climbers who pushed out their stay to the max, missed their ferry or it was already full or something (to morroco) and camped out in the carpark to get one the next day.
Some Spanish official checked them out, almost fined them for overstaying the one day but checked the video in the carpark and saw what time they bedded down in the carpark the previous day and let them off, only because they were there the previous day. Someone else that was there who was over by a bit longer definitely got fined.
Think it might be a bit of a lottery. And I think the fine is a daily rate?? It can rack up pretty quick.
Turkey is another good spot for whiling away some non-schengen time...