Too much proof. However, Vlad did use a "not right" clause in his fight with Austin. He did not use his right at all, only his left! So........Vlad used that clause!
If a boxer feels that they are unable to fight to there highest ability in a fight they shouldnt sign up for it. If for reasons they are suffereing emotionally etc they should either pull out or man up and take the beating. So the answer is no - we dont need anymore excuses in boxing