It seems that McDonald's on Friday and Saturday night is a great source to spot. In my hometown, McDonald's is opened 24/7 during the weekends. However, this is just the drive through and not the restaurant itself. Between 4am and 5am on Saturday and Sunday morning (or Friday and Saturday night, however you prefer to call it
), it is always very busy in the drive through with people returning from the pub, hungry because of the alcohol. I have girls trying to get into the restaurant to use the toilet, but then discovering that the doors will not open because it's just the drive through that is open many times. And as many times as that, I have seen those same girls squatting next to there cars or in a dark corner of the parking lot.
All in all, it is a great place to go during a party night, order some food yourself and just sit in your car. You have a great reason to be there (eating), desperate girls who think they can use the bathroom will be out of luck and as they are all inhibited by alcohol they can't hold it anymore and go in the parking lot. To top it all off, McDonald's will provide every order with a napkin, so the girls won't have to worry about wiping either