Yeah, it depends on what happens in the way of buying and selling. Generally, people don't tear down unless they have to leave early. We also ask people not get the additional machine rewards if the machines don't stay, so a lot of them do.
A majority of the show stays though. While stuff can leave the arcade room, our community rooms (with over 50 machines themselves, although mostly vids from two different arcades) and our museum rooms with 150+ consoles stay hooked up and playing until 5pm. We have a bevy of speakers on Sunday too, and the vendors generally stick around until at least 4pm.