Interesting thread, although I think a number of you are trying to assess a potential threat based only on one or two aspects. In reality, it's best to assess the totality of the circumstances.
I know BillCA is talking about visual cues from people, but let's expand that a bit, as the same person exhibiting the same cues will trigger alarms to a degree that's determined by the surrounding environment or circumstances.
In other words, a highly tattooed Hispanic male looking your way may not raise your condition to orange during lunch hour on Rodeo Drive, but that same person at night and right smack in the middle of MS-13 turf most probably will.
Let's assign this a points system: 80-100 points puts you in condition red, 60-80, orange, and so on.
Location: Upscale mall in Upper Arlington, Ohio = 1 point. Certain areas in East Cleveland, OH = 9 points.
Time of day / Lighting: High noon = 2 points. Well lit area at night = 4 points. Dark or poorly lighted urban area = 8 points.
Clothing: Business suit = 2 points. Hoodie with gang graffiti on it = 9 points.
And don't discount that "6th sense" that a lot of folks have. I believe that a "6th sense" is your subconscious analyzing all of the above when your conscious mind is centered on other things.
And so on. These are just for the sake of the discussion, but you get what I mean. Add up the total
number of points to determine the proper "condition".
Now the problem with centering your attention on only one or two factors is a form of tunnel vision. When you focus too much on a person's eyes or dress, for example, other clues that might make a critical difference go by the wayside.
They were The Blue Knights MC.
There's probably some here who aren't familiar with them, Tourist. To all, the Blue Knights are a nationwide motorcycle club made up exclusively of commissioned law enforcement officers. (And just for trivia's sake, Tourist, did you know there is a nationwide motorcycle club made up of retired LEO's? Know what they call themselves? The Retreads