I was at the UPS hub in League City - I was there sending my Tomcat back to Beretta for repair.
Of course, I had some pretty big clues - there was a camo painted truck parked right by the door advertising a certain online firearms and ammo store. When I got inside, the gentleman (the only other customer) was picking up several boxes of ammo. I was standing behind him - he was wearing a black t-shirt and I couldn't see any bulge at all. Then went around the counter so that the UPS lady would not have to lift the heavy boxes.
He leaned forward and there it was. He went from no bulge at all to printing like a Gutenberg press.
But I was still impressed. The t-shirt was not very loose on him and yet he was concealing very well until the leaned over. I sooo wanted to ask him about his rig - but, of course, I didn't.