I've got one of those, who is also not the billpayer. I've tried to explain it, but with mixed results. His latest trick is to turn on the oven to cook a ready meal, and then forget he turned it on, which goes down well. Believe it or not, he even did that during the heatwave. Mind you, we're talking about a lad who once came home from school, turned on the TV, and then only an hour and a half later, noticed that there was a seagull in the room with him.
We've got two long term hotel guests.