Quote from Joey in The One with Phoebe's Birthday Dinner
Waiter: It's been an hour. The maitre 'd has asked if you'd be willing to reconsider switching to a smaller table.
Joey: Maybe we should just eat now.
Waiter: You can't order until the entire party has arrived. Restaurant policy.
Joey: Well, how about this? Another table leaves, right, but there's still some food left on their plates. Okay, what's the restaurant's policy about people eating that?
Waiter: It's frowned upon.
Joey: But it happens?