Bogus dining, would one still have to pay, or can they get away (details inside)?

Let’s say you have a party of 6–8 teens and they go to a restaurant. They order steak, lobster (if available), other expensive plates, extra sides, and such, with desert. After the salad, or soup (don’t eat them so I don’t know which is served 1st) with sufficient time to assure their meal is being cooked, they ask for the check to pay for the soup or salad and the drinks and that is all. They ordered the meal but have not received it, but if it has been started for them, can they get away without paying for it, even if it was an expensive plate? Do they have to pay because they started with the appetizer, soup, or salad? If they don’t have to pay, does the restaurant or diner have to eat the cost of the meal because you can’t just put it back on the shelf, or know someone else could order it as if it were a hamburger all being made the same?