Right Of First Refusal. That's what Disney has when someone sells their points. If Disney excersises their ROFR, they buy it back before the buyer gets to.
Disney has the right to buy any DVC contract that is offered for sale for the same terms as the prospective buyer. If you are selling your contract, you must submit the offer to Disney to see if it wants the contract before you are allowed to close the deal with someone else.
Right after I posted this I figured it out. Thanks for replying, though! Why would they buy them back? I guess to just rent out the rooms for awhile and resell them at a higher rate later?