I think if someone does notice a concealed firearm, you must not be doing it right... 99% of the people don't notice, or at a minimum don't care when I open carry.
I think I would add to this, either you are NOT doing it right, OR the person looking either carries or is in law enforcement. (Focused at noticing)
As far as I know (Could there be times when someone doesn't tell you, sure, probably more likely) I've only been ID'ed once. It was by my friend who has seen my gun AND is an ex-Police Officer..
I carry IWB (Tuckable), in my back about 5 O'clock in a left hand holster.. Pretty well concealed but if you "know" what you are looking for, you can figure it out.. (Large metal clip over black belt and slight bulge in pants)
I've also ID'ed two people..
One, was at a
Link Removed Dinner Party. He was wearing a Cuban style (square bottom shirt) Harley shirt and the shirt rode up and got caught on the holster exposing his Kydex OWB holster.. I mentioned it to him, (I sat behind him) and he pulled down on his shirt and never looked back at me..
Two, was a HD Street Glide going down the street, again with a shirt (untucked)with the wind flapping it around. He was carrying a SS 1911 in an OWB holster. The barrel kept being exposed as the wind flapped.. It was rush hour traffic and I never got next to him at a light to tell him..
I will tell you that, since I carry, I am usually looking at people, especially at check out counters (What else do I have to do???) to see if I can spot someone carrying..