Tons of threads about people who booked rooms for others and the others incurred charges, trashed the place, smoked, emptied the mini-bar, etc.

First rule is to ask yourself whether this is a person to whom you would provide your CC or a key to your house for use when you're not home. Unless the answer to both is "yes," don't do it.

Now, you either don't mention it and eat it and resent the guy, or you collect from it, he thinks you are chear and he resents you.

Want to do something nice for him, give him a gift card. When it hits $0, it's only useful to jimmy car doors.