I had to respond to this thread. Just a little background. Bear with me.
As some of you may know, I'm former law enforcement. After I left that profession, I went back into the restaurant business. I have worked as a manager for many different restaurant companies. This includes most of the major restaurant chains. In every single case, the company had a policy forbidding firearms on their premises and/or carry by their employees.
The reality of the restaurant business is that this policy ends up being an individual franchisee decision, but most go along with the franchisor recommendations.
Currently, I am a manager for Denny's. I admit that the no guns policy bothers me. I won't say how I handle that situation. As for the food and cleanliness...my restaurant was just built and opened in May. This is the cleanest restaurant I've ever managed. And I would stack up the quality of our food with any other restaurant of the same type. (i.e. IHOP, Waffle House, etc...)