After hearing several pose the question and/or assumption, I decided to find out exactly what the policy was. I called dining reservations and asked; she put me on hold while she consulted a dining supervisor...After a lengthy wait, she told me that Disney does not automatically cancel dining reservations when a vacation has been cancelled. If the party does not cancel their ressies, then they will remain!!!! I definitely do not agree with this!!! Families could actually miss out ongreat dining experiences, due to a faulty system...however, my opinion is probably not important to them, but this is a definite flaw in the system....This could actually be a way to get second-chance ressies when someone cancels at the last minute, if ressies were cancelled automatically....So, if you're counting on someone's cancellation to help you get a ressie, then you are out of luck unless the ones cancelling are courteous!!!!