King hit isn't just a sucker punch, people have died from them. It was so bad in Sydney that they had to change their night life laws because people were getting punched in the back of the head and dying so often in the club district. And they weren't in fights, they were just random attacks.

(By "so often" I mean like two or three in a few years. We're not accustomed to people just getting shot/murdered all the time like America is)