Great stuff.
People do read body language and react to it whether they realize it or not.
This is a long-established tendency studied many times with success.
It’s where, “I just don’t like that person” and “Yeah, s/he made a good impression” comes from.
ALL police forces STUDY body language.
I can describe the “thug” culture to a tee .. my neighbor was astounded when the guy (who lives a few doors away) did exactly what I told her he would do; he was getting out of his car in the parking lot, and he just could not stop himself from snooping in the windows of the car parked next to him (even to the point that he walked around the entire car .. which says .. I’m looking for anything I can hoist, so I can sell it for drugs. And, he was also looking to see if the keys were in the car.
The thugs try to tell us it’s “profiling”, but it’s actually something that thugs do that causes them to put out a negative profile of themselves; it’s how they walk, hold their head, make certain gestures.
Most police units are trained by studying body language. It can and does save their lives.