Hitting an opponent after the bell on purpose can be a serious career killer in the UFC, ask Paul Daley. When he sucker-punched Josh Koscheck after their bout at UFC 113, he got fired immediately and forever by UFC president Dana White.
Last Saturday at UFC 185, Ryan Benoit pulled a similar move, and although it was not as stark as Daley's punch has been five years ago, it was still a questionable one. After having a hard time against Sergio Pettis in the beginning of their fight, Benoit turned the tables with a knockout blow in the second round. He then delivered an additional kick after the bell to the rear end of Pettis, who was laying in front of him unconscious.
Even his hometown crowd didn't appreciate that very much, as they immediately started booing. Lucky for Benoit, Dana White has no hard feelings towards him, as he mentioned at the official post-fight press conference.
"The kid was fired up," White said at the UFC 185 post-fight press conference. "He did it. He immediately apologized afterwards. [...] When someone apologizes and realizes what they did and apologizes, it's all good."
(Transcription via MMA Fighting)
Benoit faces no punishment, fine or anything. You should have apologized, Paul.