I did at the one in Vallejo and the rent-a-cop wanted to kick me out, but as soon as I turned around he's like "Oh, you're one of those guys who carries his gun". My response WANTED to be "Here's your sign", but all I did was say "Yup". He called the manager over to the front door (after not letting me past him) and the manager says "Don't worry about it. He's completely fine... Sir (meaning me), all I ask is that if you're going to do that in my store, please keep your hands off it." My response was "No problem..."
So I'd say go for it!