Can they kick you out of Souplantation/Sweet Tomatoes after a few hours, even if you are still eating? We plan to go their at 2pm and leave at 6pm. Do they have the grounds to kick you out between meals?
OK, you are probably not going to like the response I'm going to give.
I work at a restaurant and other restaurant workers really don't like people like you. You're what we call "Nester's."
Now it's one thing if you want to sit around and ring up a bill to over $1,000. That's worth the time you're putting in. But when you only spend about $10 per person & run the server around, you are wasting a LOT of peoples time. The server could have had someone at that table who is going to spend money. In 4 hours, that table could have been used 2 or possibly even 3 times. The kitchen is not being kept busy and the restaurant loses money because you aren't spending any. You're also being disrespectful to other guests who would like to come in and dine, but can't sit because you're busy wasting your life away in a restaurant. You could also be cutting into other peoples reservation time. It's even worse if you do it late at night when restaurant employees are ready to go home.
Now to answer your question, a manager can ask you to leave, but you don't have to. There is no law stating that you can only spend a certain amount of time at a restaurant. It's highly unlikely that a manager in a full service restaurant will do that because to upset anyone means that bad news will travel around about their place. Maybe you should call ahead and see if you can rent a table out for four hours so as not to upset anyone.