After being at the hospital a few times this week, it seems the parking commisionaires have a little trick going on. Each time I hand them $10 bill for an hour of parking they lift the arm up to exit immediately before giving you change back. I am sure that some people fall for this and exit right away, without getting their change. They thank you immediately hoping you will leave without your change. I think that some people trying to leave have other things on their mind at the time, and fall for their sneaky trick. Please don't let them take advantage of you this way.