After sending two rather lengthy e-mails to the cup chiefs at ClanBase, followed by an even lengthier IRC discussion with Ginga_Ninja, who is in fact a cup chief at ClanBase. I discovered some 'rules', for want of a better term, which aren't very evident on their cheating policy page. Some of the interesting things which I discovered follow.

Unless a cheater was shown to have cheated in a ClanBase game, the official ClanBase games in which he played will not be forfeited.