I'm not familiar with this C'thun trash skip, but I assume you mean this:
http://wow.joystiq.com/2006/11/06/ov...heir-permaban/
I'm not sure how accurate the term "hack" is in this article, but if it was a true "hack", that is far, far different than what was going on in ToT for Ji-kun. It was perfectly doable by anyone in the game using nothing but the standard game client and pressing logout at the right time. Not only that, but, tops, they had to ban 40-50 people in the c'thun scenario. Potentially
thousands of people did the Ji-kun skip, and it is
highly likely that they have no reliable way to pick out the people that did it.