but most standing locks are available in JJ
The guy obviosuly didn't want to continue fighting.
Another student of mine was the victim of an attempted mugging. My student, Keith, was drunk and waiting for his wife to pick him up from outside the niteclub when two guys approached, threatened him and demanded his wallet. He did a double-leg on the first guy, got mount and broke his arm with an armbar straight away. The guy started screaming and his mate ran off.
So, yes, they do work.
**** the details.