Not to beat up on you, but you did post it in the public part of the forum, I have to say, I think you were wrong. The place was posted and like it or not, they have as much right to ask that you not bring in your firearm, as you do to have your firearm in your home or on public property. I'm glad you posted it here as a heads up to the rest of us, but I feel you were in the wrong for concealing and proceeding instead of leaving or putting the pistol in your car. It's a personal decision but we're trying to enhance the view of the public of gun owners and violating private property rights, I believe, isn't the way to do it.
FWIW.