How about just scheduling the show until 1 or so on Sunday? Or do like an annual old car swap meet does here- admission is free on Sunday, but they warn that many exhibitors leave early, so you takes your chances on Sunday.
For that matter, why does everybody have to have shows for 2 days, anyhow? I'd be much more likely to participate if I was only wasting one weekend day instead of both. Annual hot rod show here is scheduled for 2 days. Everyone leaves the fairgrounds on Saturday night, many for their motel room, many heading for home. Sunday is a much smaller show, but still big enough to make a showing.