"As far as I know they can't make you stop carrying. They can ban you from the restaurant if they find out but if it's concealed it's concealed and I don't believe a company can make it illegal to carry a gun on their premises"
This is correct in VA. The PD can be called but you have to be given the chance to leave. A manager could ask you to leave and if you refuse the officer can only make the arrest if you refuse to leave once he hears the manager tell you. BUT, always a but, the manager can go to the magistrates and swear out a Trespass warrant for not leaving once told. This is a Class 1 misdemeanor in VA so an officer can ID you for the restaurant and they could technically obtain a warrant. In my 30 years as a LEO I never saw this happen as businesses just want people to leave. They don't like being the bad guys and going the warrant route.
"The More People I meet the More I Like My Dog"