Exactly, and the job of policing the franchise owners falls to Denny's Management.
The worst thing a franchise food chain can do is allow it's franchise owners to destroy the brand. It's like a cancer that spreads and taints all of the locations to some extent, even the well run restrauants.
McDonalds is particularly vigilant. A Big Mac tastes the same in Cleveland as it does in Miami. Denny's could take a lesson from their consistency. From what I see now, eating at Denny's now is something of a crapshoot.