I’ve seen this picture around the internet several times over the years, and I’ve seen it making the rounds again recently. It came up in a post where someone was asking whether or not this sort of thing was applicable to people carrying lawfully.
I spent a long time working a job where I conducted a lot of video surveillance on the general public. I used to play “spot the concealed carrier” and I like to think I got pretty good at it. The biggest give-aways I found were the folks that would come in shopping wearing the concealed carry uniform (baseball cap with a velcro patch on it, tactical belt, expensive boots, expensive sunglasses, plaid shirts, knife clipped in the pocket, etc).
It was common to zero in on someone wearing the “uniform” and eventually see a tell that gave away the fact that they were carrying. An eventual adjustment of the holstered gun in the waistband, obvious printing when bending over, just having a close look at their waistband and seeing the printing/bulge, that sort of thing.
Also, while I’m on the topic, I can address one more thing: I always hear people who open carry talk about how nobody ever even notices when they are OCing. Trust me, people notice. They discreetly call security and tell them that there’s someone in the building with a gun. Whenever someone would come into the place I worked open carrying, trust me, I knew about it. I’m not saying I’m against open carry, but don’t think that nobody is noticing.