Concealed is the key. While I was working security details some years ago with my Dad...my favorite concealment t-shirt was an old one, with a rainbow peace sign. I also tend to wrap small "pocket" pistols in paper money, topped-off by more, deliberately crumpled ones....to drop, diverting attention, while the main "wad" makes its appearance. Nothing like cash to distract a crook! I also find the bills aid a smooth draw, preventing the hammer from catching on clothing.
Experience is the best teacher...and I was blessed by some old timers' advice early on. I am trying to continue the favor. 'Worked for me...thank God.
Very ingenious, I've not heard this idea before!