My oldest son is a LEO. He says that is NOT an approved restraint position in any department in the United States of America. I'll take his word for it.
Well, looks like your son is wrong.
It was a very common restraint technique until a few years ago and some PDs, have never banned it.
https://chicago.cbslocal.com/2020/05/29/chicago-police-deadly-force-policy/
“My oldest son is a LEO. He says that is NOT an approved restraint position in any department in the United States of America. I’ll take his word for it.”