How far away from civilization (or the next supermarket) do you need to be for these prices and fees to make any sort of sense, that anyone even remotely thinks about taking a single drink? I've never seen something like that in Europe.
My solution was to go to the convenience store (still located in the casino) which was expensive (a guy in front of me nearly had a meltdown at paying $15 for a can of lager) but at least had no "restocking fees." A Target with more sensible prices is about a 10 minute walk from MGM Grand, however, in case anyone here ever winds up there.
So, basically, drunk people and children.