let me refer to a concrete example from my own experience where I was just trying to survive the legalities of the situation with 50 witnesses.
Someone who I deem to be a pretty weak fighter attacks me in a drug induced rage because I attempted to break up his fight. What should I do?
1. Beat his face in ring-sport style and risk jail?
2. Use some chin na that would never be useful in a ring setting to incapacitate him util the police arrived?
I chose to stay way on the good side of the law and used chin na.