The first time I had that argument was in 1996(?), with a NC shop owner who posted a no guns sign (which had force of law). After I gave her the above explanation (politely, of course) and told her I'd be happy to return after her sign came down, it took about 3 weeks for me to notice the sign was gone... I was happy not to have to haul my shirts to the cleaners near my office. That place was hard to get to, on the wrong side of the highway..
Education can be powerful stuff.
