Late night sighting

I went to Denny's for dinner one night, around 2am, and this guy goes up to pay and leave. As he is heading for the door I see him start to wave his hands, like he is trying to trigger the automatic door. Only the door isn't automatic. He stands there for a second then asks the waiter how you work the door. They waiter tells him to push on it. I almost died!! I couldn't believe it. Too funny!! Later I wonder how he got in in the first place. Did someone open the door for him, or did he just forget that he had to pull on them to get them opened?