Realistically, LTC holders in Texas are less than 10% of the population. Even if everyone on of them were firm in the conviction not to do business with anti-gun establishments, there won't be much of an impact. But I seldom miss an opportunity to talk to friends about those businesses. If someone mentions Sprouts Farmer's Market, for example, I make a point of suggesting alternatives. My personal experience is that Sprout's doesn't turn over their vegetable stock as quickly as others to there is fresher produce to be had. I don't have to even mention the 30.06 signs on the door. Someone else mentioned AMC versus the Movie Eatery and I never fail to talk about how much better ME experiences are and how the AMCs that I've visited weren't well kept, which was the truth.
Persistence can help to win the battle. There are lots of reasons besides their anti-gun policies not to visit places like Dick's. I just make sure that I have them available in discussions. I think you can call it a force multiplier.
