***We welcome families, but if the natives get restless, we'd be happy to pack up your meal to go." ****
That is a great idea. The problem is, it is an offering instead of a demand. Breeders would ignore it, and parents don't really need to be told what is the appropriate thing to do, they already know.
I would like a sign that said something to the effect of rude loud obnoxious behaviour will not be tolerated inside the restaurant, regardless of age.