I think it falls into the category of 'good sportsmanship'- a coach should be a good example, and expect his students to be good people too - otherwise you are in a moral dilemma about teaching them something that could be incorrectly applied to hurt the innocent.
But if you want enlightenment - you probably won't find it in the gym...
"Never interrupt your enemy when they are making a mistake."
--- Napoleon
"MonkeySlap is a brutal b@stard." -- SevenStar
"Forgive them Lord, they know not what MS2 can do." -- MasterKiller
"You're not gonna win a debate (or a fight) with MST. Resistance is futile." - Seven Star