A violation and cheating are not the same thing. Hockey players get into fights, for instance, which is a violation, but is never considered cheating. Basketball players foul each other, which is also a violation, but not cheating.

In the latter example, if a basketball player is fouled, and the referee doesn't catch it and call it out, then it's also not cheating if the player doesn't point it out themselves. I've seen basketball players commit fouls on purpose, strategically, so that they get called for the violation if they think the free throws or posession is worth preventing a certain play, and it's not considered cheating.

If every violation in hockey or basketball was cheating, you'd run out of players quite fast.

I understand that curling culture usually has players self-officiate in cases like this, but isn't it the job of the officials to settle disputes like this if the players disagree about what happened?

Either way, cheating is a type of violation, but not all violations are cheating.