Whatadumb thing to do.
Actually, it's not.
When open carry was being promoted last year, a dumbass group of supporters took it upon themselves to demonstrate in Fort Worth fast food locations. They carried AR-15s into the stores and held them in a "ready" position with their fingers on the trigger.
They came off like a bunch of threatening thugs, ready to spray the customers on a moment's notice.
I can assure you that no restaurant chain wants that kind of behavior in their stores.
That particular incident also came close to sidetracking the whole open carry movement, as well.