The way I see it, seeing someone walking around Home Depot with a gun on their side would at minimum cause me to do a threat assessment. Bad guys come in all shapes and sizes, but I probably wouldn't go on alert if he was clean cut and honest looking. If the person passes muster I probably wouldn't give it any more thought. But that's me. How the rest of the public treats it is another story. "OH MY GAWD, HE'S GOT A GUN!!!!!". Yawn.
Like it or not, there is a large group of people in this country that think the very sight of a gun will make it jump up and shoot them right between the eyes. You think they're stupid, I think they're stupid, but they won't change they're mind no matter what.
Unless you drop one from the fiftieth floor or can pitch one at 100+ mph, a cell phone isn't perceived as a threat to the general public. If they only knew that they're all going to die of brain cancer they might feel differently, but what can you do? However, there isn't anyone that doesn't know a gun has only one, potentially deadly purpose.
Whether it's ignorance or fear or just a belief that the world would be a safer place if only the government had guns, there are people everywhere that don't feel comfortable around a gun. I do have to admit, I would be uncomfortable if the guy carrying the guns around had a bunch of gang or biker tats and looked like he's strung out on drugs. But then again, that's what a threat assessment is for.
I look at it this way, I don't like it much when people force their beliefs on me. But I have to respect that they're entitled to their opinion. Consequently, as a tried and true atheist I get really ticked off when some atheist jerkoff insists that the high school football team can't say a prayer before a game because one kid in the school, (who probably isn't on the football team in the first place), doesn't believe in God. I think that's just wrong. I also think it's a tad uncalled for when when one of us decides they're going to singlehandedly going to march around with an exposed gun no matter what anyone thinks. I think there should be some middle ground. I live in an OC state, (NV), but in the 17 years I've been living here I have never once seen an OC in public. But I also know I have undoubtedly been in close proximity to hundreds of people that are concealed carrying.