AFAIK and CMIIW, I haven't see someone forgiven for cheating in the same campaign, what I know people forgive when the case is in grey area e.g. exchange merit, ban evasion, bought account etc. When someone ever cheating, it's like people will see them as a cheater forever.

So if you bust them, then you would see negative feedback on their accounts.

But wait, you said all of them aren't in campaign, why you worried if this forum are their main source of income?