My contract offers penalties for cancellation, as well as non-payment of final monies due which are quite enforceable. Bascially the person renting my points signs that they are aware that if they don't pay the last payment by the due date, I'll cancel their reservation and they forfiet the deposit. If they decide they want to fight it, they have to do so in Florida.
By signing the contract they agree to the terms (as do I) and it covers my butt.
Also it has a force majuere clause that states that if for some unforseen reason beyond my control Disney cancels the reservations (such as part of the property being destoyed by any given peril or act of God) I will make a reasonable effort to try to reaccomodate them elsewhere, but if I'm unable to, the only thing I owe them is the return of their deposit. In other words if the place burns to the ground and I can't get them another room, I can't be held responsible for their plane tickets and such.
Anne