Do all cars have to be out of the building by 4pm, and is it possible to keep the cars in the building till Sunday morning?

Just a suggestion for next year, Tom.
Please make information like this known before the show, so that if somebody hires a hauler to drop off his car on Thursday with a pick up scheduled for Sunday morning won't be surprised when his car gets dropped off.
Parking lot security already seems to be an issue, but I had no idea of what the storage arrangments were.

My bad for not asking first before making my arrangements, but as a first timer, this would good to know ahead of time.
Andy