Thanks, Sam, good thread.
Subtlety is important in being "gray". Your head-on-a-swivel comment is a good example. I was in retailing back in another life. My positions gave me an opportunity to observe how bad guys (and girls) acted while casing a store. The best were the most subtle. Small movements, slow movements of their head and body along with natural actions associated with shopping.
When a security person would notice them, and often security was more obvious than the shoplifter, they would slowly move on to an easier target.
Lesson learned from those days payoff now when I carry concealed into a strange environment. You'll never know I am aware of your presence until you get into my personal "space".
There is a skill to scanning for trouble. The secret is, don't look and act like you have a secret. Watch what people in Condition White do. Do the same thing, only be in a heightened level of situational awareness.
Practice and have someone watch you practice, someone who can be brutally honest with you. It will pay off.
Freedom has a taste to those who fight and almost die, that the protected will never know.
"Comment is free, but facts are sacred." C.P. Scott, 1921