I am not overly worried about people being able to carry in a gun show, it is up to the venue owner, the promoter, local law whether or not to allow concealed or open carry. I would certainly be in favor of rules that there is absolutely no drawing of loaded weapons in the sales area or halls.
In VA if the show is in an publicly owned venues they cannot restrict open or concealed carry. I have not looked into the details, at the Hampton show there is a table near the entrance where the police sit and apply flags to show that actions are locked open. I do not know if this applies only to guns for sale or not. All guns for sale have to have their actions open and be unloaded. But, I have seen at least one person open carrying on the floor, and I would assume others concealed carrying as well. I cannot swear the open carry gun I saw was loaded but it did not have the magazine pulled or the action locked open.
Any VA posters in the know on the specific regulations?