Can you bring a birthday cake to a restaurant? Viral pizzeria dispute reveals the rules

A viral confrontation at a New Jersey pizzeria over a child's birthday cake has put a spotlight on the unwritten rules surrounding outside food at restaurants — and what diners and restaurant operators should do when those rules collide.

The controversy began after a family celebrating a 5-year-old's birthday at Joey Tomato's in Point Pleasant Beach, New Jersey, brought a cake into the restaurant and later asked for a knife to cut it. Family members said they had called ahead and received permission...