I had a similar experience. Was at a restaurant eating dinner at the bar with friends, one of which knows I carry. They were talking about the new gun laws and I was staying out of it. That crap only gets me angry. They share my mind frame, but it is basically just us ranting about damn lawmakers, Dems, moon bats...etc.
A guy sitting a few seats down overhears us and decides to come over and join the conversation. I sat quiet during he whole thing, nodding at the appropriate intervals. The conversation then leads to muzzle velocity, AR-15, Bushmasters, and such, and it begins to get intricate. This guy obviously knew his stuff. At one pint in the conversation the new guy says, I agree that you should be able to carry but I don't, and with that, he lifted up his shirt. My buddy on the other side of me also said, yup, me neither.... then they turn to me, and I gave my buddy the most evil stare down I've ever given. The conversation abruptly stops and we continue talking about the Pat's bye-week.....