This is a messy issue. I think that if my gun remains concealed, and is not used to harm anyone, my disregard for their silly sign harms no one. Their wish that I surrender my right to self-defense in order to associate with them is absurd. I am thus inclined to ignore it. Then again, if I can avoid doing business with people who would deny me my right to self-defense, that would be preferable anyway. But then again, these signs are often posted due to the dictates of corporate bigwigs, or may even be mandated by local law, which makes ignoring such arbitrary commands from the political class worthy of defiance.