Some observations
Just because there are some partially cracked eggs out there, AKA mall ninjas, tacti-cool rubes, Rambo rejects, mili-morons and such, please don't sterotype people just because of outward appearances alone. Don't get me wrong, some people are what they are at face value, that is walking ID10T errors, but some people, like myself, may wear certain things because they work well or feel comfortable when doing things like hunting or we might be wearing them while in between hunting stints during the day.
The last gun show I was at I helped a customer/business associate with his table. There was a gentleman asking me about a pin-on MAK-90 TAPCO muzzle brake he was selling who had just bought a shotgun from another vendor and it had the buttstock cutdown to just about a half inch behind the end of the wrist to make it a pistol grip. While we were talking about it and what he needed to do to stay legal (as I am a gunsmith/gun shop owner) since we were talking about the legalities of modifications to his MAK he said he would just take his MAK to TAPCO since he didn't live far from them in Georgia.
This man was in Missouri and was a Georgia resident. He just bought a shotgun from someone at that gunshow. As a dealer I cannot sell to customers a handgun unless they are a Missouri resident or a shotgun/rifle if those people live in a state other than one of the states that borders Missouri unless I send it to a licensed dealer in their home state, yet this man bought a shotgun from someone at the show.
By itself I was uneased by that situation from a legal standpoint, but the man seemed alright to me otherwise. He looked to me to be "safe" by himself and was dressed like a construction worker. When he came back around with three other friends, one older and two younger, the group together made warning alarms go off in my head because of the expressions on their faces, their body language and the way they spoke together. My friend sold some ammunition to the youngest one who looked to be in his early 20s. After they left the area of his table, I told him that those were the only people that made me feel uncomfortable at the show, even though others I had met during the show may have dressed a little odd, they talked and carried themselves like what I consider "safe" people. I was glad I had no firearms to sell on the table as if that group of four had asked to buy any I would have refused the sale period, with or without the 4473, as the men as a group made me uneasy. I listen to my gut instinct.
Personally, I was thought to be an undercover ATF agent because I wore loose fit blue jeans, a polo style shirt had fairly short hair, military surplus combat boots on my feet and I had a small folder with copies of my FFL and sales tax exemption form with me in case I wanted to buy something for myself or for resale while I was at another gun show earlier this year. I understood the perception because of my folder, but I had to wonder how my clothing looked like I was a BATFEag.
At gun shows in my immediate area, say a 20 mile radius from where I live here in rural Missouri, at local gun shows you can tell who the LEOs are with tables because they have boot camp cuts, talk with an aggressive edge in their voice and dress like they are boots in camp. Some even have a holstered sidearm in plain view without a badge displayed or any other means of identifying them as LEOs to someone who doesn't know who they are. The rest of the people at the shows, vendors and customers, look like regular country folks with jeans of all kinds, shirts from polo to flannel and perhaps a pair of bib overalls and a well worn baseball cap. Those that "talk big" generally are the mil-surp collectors here and they are just really rabid gun-nutties who read alot. I know they are harmless because I know most of them personally or by reputation from others who know them.
What do my words boil down to? Someone can look like they are a LEO but they raise warning flags in my mind. So can someone who looks like the typical safe Joe Six Pack. For that matter even hunters dressed in camo or blaze orange here during deer season eating in a restaurant or getting fuel can either make you uneasy or not just because of their body language, vocal signals (inflection, word choices, etc.) and the vibe they send out regardless of clothing.
Back on topic, the mall ninjas are rare here as we have no malls save for small strip style ones unless you drive about 1.5 to 2 hours to a larger population center. Even there the security personnel are more along the lines of the parking lot grandpa who helps you with your flat tire or a jump start in his little compact pickup truck with the yellow flashing light on top or the grandpas who take the job to have something to do and mostly help kids find their lost parents or take things to lost and found. Since I don't go to St. Louis or Kansas City metro areas much if at all, I guess I avoid the real mall ninja hordes.