Why not announce on the flight that there is a possibility for someone to stay overnight, and comp them. I am willing to bet that you'll find someone who will stay. If that person is not in F, give the bumped flyer complimentary F on his next flight or something.
OR Put one of the two flyers on another airline, if possible.
[This message has been edited by billyeggs (edited 07-21-2002).]