I actually take a different approach and I'll explain my take on it. I never wear anything that suggests "tactical"...you know, 5.11 pants, Blackhawk or Wilderness instructor belts, etc. And I don't wear anything that says I'm pro-this or anti-that. The way I approach a possible situation with an active shooter of some type is that I don't want to make myself more of a target in any way, shape or form...I just want to blend in and appear to be a nobody until it's time to act if I'm forced to. And wearing suggestive clothing only puts me in the cross-hairs that much quicker in my opinion. Especially if the shooter decides to case the area (even for as little at 30 seconds) before acting. I know if I were playing the role of the bad guy, the first targets would be my tiny-brain instinctive ones (the larger adult males nearest to me) and then next would be those targets that indicate that they may be a threat in some other way, i.e. possibly armed.
To play devil's advocate, I suppose wearing something that suggests you may be carrying may give a bad guy a second thought before approaching you in a mugging or car-jacking situation...but I prefer to rely on my situational self-awareness of what's going on around me. I try and maintain Cooper's Condition Yellow from the moment I leave the house in the morning to the moment I return that afternoon. It's really not that hard to do after years of practice. Google Jeff Cooper's Color Code if you're interested...
So, when I'm out dressed casually, I'm just another guy with Bermuda type shorts, comfortable shoes and a nicely pressed, but un-tucked shirt. Not trying to start an argument, just stating my approach.
