@10 Hi Galaxie Pete:
Good story.
Like you, I learned martial arts (Japanese ju-jitsu) decades ago, long before MMA was introduced to the US by the Gracie clan. Everybody else in my neighborhood boxed, but I played the piano and trumpet and didn't want to take a chance injuring my fingers or my lips.
In jujitsu training we were taught the several dangerous strangulation and choking technique, and how to escape them, but sensei let us practice no more than twice per session because he didn't want to take a chance that a student could get hurt in their tracheal or carotid artery area. If I was choked or strangled twice in a session: "OK! That's it! Next student!"
The US Army taught some of those lethal techniques in hand-to-hand combat training, but the Rangers and SF guys got much more of that training in their programs.
When I went to FLETC years later, we were taught how to restrain someone from the rear without having to apply pressure to the neck/throat region. FBI SAs are taught the same technique (my agency sent me to the FBI DT program years later).
When we see these submission moves by American cops from any jurisdiction on suspects, you and I both know this is official application of an unofficial technique.
I'm off to bridge now, so we'll have to continue this later.
