A few days ago, I walked into Fas Mart carrying openly. I was told by an employee that "we don't allow that here unless you're a cop" and I was pretty upset about it. I wrote a letter via the corporate website expressing my displeasure.
I got a call from someone at corporate who said that not only do they have no such policy, but that he would make sure to straighten the situation out and provide some instruction for the employees at that location. Their policy appears to be similar to starbucks, et al. They have no policy at all, if it's legal where you're at, they don't care.