If you were told this by a Disney Dining CM, then I would take it with a grain of salt. I am positive a strategy for this extremely worst case scenario has not even been developed yet. Can you imagine the PR nightmare if they do not honor ADRs made before October 14?
Also, one time I had two vacations on the books, but the first one was canceled, literally, the day before we left because I had emergency surgery. DH talked to an extremely nice lady in guest relations who helped him and one of the things she offered to do was cancel our ADRs. Only problem is that she canceled the ADRS for the second trip too. We showed up at Disney with NO idea this happened. The restaurants were able to see on their computer system info the name of the CM who canceled and also the date it happened. We were seated at every single place we'd booked. The restaurants' computers should have some explanatory info that backs up your story (and that of others in this sad, stressful position), IMO.