I suppose it's possible that Joe Moocher is doing this trip on frequent flier miles (it sounds like he has been traveling a lot, and miles go to the person who travels, regardless of who pays the bills) and can get cheap mass transit from the airport (I could get to one local airport from my current apartment for $2.50, another for $7.50).
It does seem increasingly likely, though, that he is mooching because he (thinks he) can get away with it, and that any meals someone else provides, and any hotel rooms not paid for, mean he can use the money for something else.