At the weigh-in and press conference boxers who will fight in the ring, meet face to face.
Some can not withstand stress and try to prove to his opponent that he will lose.
This usually happens with their fists or daring attacks towards the opponent right in front of reporters.
This behavior causes a sensation and attract new viewers who will be watching the outcome of the match.
This once again confirms that all of these things, probably just a publicity stunt.