I can see a person, especailly a female, non-gun person reacting in that way. It's exactly what she said it was. Fear and Confusion. The fear part is obvious. The confusion part would be as well if none of us had ever held or fired a gun before. She was probably freaking out on the inside the rest of the time she was in the store but probably didn't know what to do. She was probably asking herself a lot of questions like this:
Is he going to shoot me?
Is he a cop?
Did I do something wrong/illegal?
Can he have a gun here?
Did he do something illegal?
If I make a scene is he going to start shooting people?
Should I call the cops?
Is it even a real gun?
Should I tell the manager?
Why hasn't he shot me yet?
If he hasn't shot me yet I guess he's not going to?
If he's not doing anything wrong I'm just going to look like an idot if I make a scene or call the cops.
etc, etc, etc
I've seen the same reactions many times before. I stay away from home 5 days out of the week on business. Since I've been gone so much my wife's cousin has moved into the house. She often times have friends over who have no idea a man lives in the house. Much less one that just walks in the door without knocking and has a really big gun in a holster on his side. They all react the same way. They go back to what they were doing, and pretend like they didn't see me. The biggest reaction was one woman held her child a little closer, but still ignored me. After I get to know these friends a little bit more they all say the same thing: "You scared the crap out of me. I didn't know who you were, you were just a guy with a gun walking into the house." I don't know the science behind it, but this has happened at least 5 times to at least 7 different people with the exact same reaction every time. It seems to be a natural reaction for someone who has only seen guns on TV or on LEO's.
The only reasons many of us would react differently in the situation described in the OP is because:
a. We have training and/or experience that enables us to know without a doubt who is right, who is wrong, and exactly what is going on.
b. Most of us have a gun under our jacket to