Sounds like yet another panty-wetting establishment that seems to think a sign will actually stop a bad guy. Likely the old knee-jerk reaction. I guess they don't read or watch the news much to see how often and how well those signs work.
Some folks simply will never learn. Certainly sounds like they need to let their employees carry and give them authorization to defensively shoot anyone who puts a gun in their face. They have to turn their back at some point.