This has already been somewhat *implemented* by this change: Signature Campaign Guidelines (read this before starting or joining a campaign). However, what used to happen in the past (e.g. in the case with Bitmixer) is that the manager/service just ignores you or shrugs you off by making accusations of potential bias. What should be happening is:
1) Banning of signature spammers (users).
2) Banning of managers that ignore the warning that they receive regarding their mishandling of their campaign(s).
3) Banning of service that don't care about the detrimental impact of their shit posters on the forum.

There are only two cases of this I think, Hilariousandco with Yobit and myself with Bitmixer.