I can remember doing that when I was living in a dorm. Basically, my roomate was in the room and for whatever reason I didn't think he'd be going anywhere soon when I left to take a shower in the common bathroom. However he left and locked the door behind him while I was showering and I had to walk upstairs in my pajamas (I was put in the basement) to get a spare copy from the desk. Needless to say, after that, me and my room key developed a very intimate relationship.
Jeremy
