In general, most folk simply are not looking at anything. They are oblivious.
Case in point. Not too long ago I bought a little Taurus PT-22 from Academy as a plinker. Academy has a policy that a "Customer Service Representative" must carry any firearm to the front of the store before handing it to you. The CSR came back to the counter while they finished filling out the paperwork and we were all talking, myself, the CSR, the Manager that had to check the paperwork and the salesman. Once they finished the CSR took me to the register and I paid for the gun. She then walked me from the very back of the store to the front doors. On the way she asked if I had any other guns and how many (Yes and a few old ones), told me her son-in-law had two guns and finally handed over the box with the gun when we got to the very front doors.
Now it's getting into warmer times down here and the temperature outside was in the mid 90s F so I was wearing the normal t-shirt and shorts with a light unbuttoned seersucker shirt. And a S&W M&P Bodyguard 380 in my pocket and a S&W 469 in a Fobus paddle holster on my hip. Even though we had been standing around talking for at least ten minutes and walking together the full length of the store she was still unaware that I was carrying and still asked if I had any other guns.
Some other gun owners may notice but the vast majority simply don't see you or your gun.