A good policy to have is to clear everything you can off the table. Regularly offer more coffee/water/soda. If they say they don't want anything more, take the glass off the table. If possible, take the candle, sweeteners, salt and pepper mills, and all other things, until they are sitting at a completely empty table. They will eventually get the message, and then, either they will get up, or decide to stay for the duration. In which case, you're screwed. Some people just don't really care, especially after dropping what they feel like is an extravagant amount(depending on the restaurant, it is to some, and isn't for other). I have a reservation at a fantastic restaurant for Saturday night, which shall remain nameless, but its my mom's birthday and we will sit as long as we want. All this being said, if someone doesn't want to get up, they won't. No restaurant will risk alienating a guest for a table, and those that do will probably not last long enough to feel its ill effects. d