Lombardian ethic.
"win at all costs"
thats why i think teams/people cheat.
the drive to win out weighs their sens of sportsmanship.
they want to be the best, and they dont care what they have to do to achive it.
its something that is practically impossible to eliminate completely, the only two ways i think it could be possible, is to either, drill it into the kids/new players, that if they cheat, they will be hammerd for it.
alternatly, more refs. if you know that theres for example, 2 refs watching you at any given time, you arnt going to risk a 1 4 1.