Why do you let people in your restaurant with cats! If you must let people bring pets in you should put them away from normal customers.

While I do not know the specific details of your question, an animal is allowed into any public place if the animal (which includes cats) is a service animal. As long as the animal is properly vested and has it's ID, the service animal cannot be refused. If it was not a service animal, I have no justification for having the animal in the restaurant.

They keep the rats down.