I could get behind this solution if signature campaign managers could agree on it
I've PM'd them asking for their opinion on this proposed solution.
There'd be little point in this; it would be more effective to report the account and get it banned. Should the account not be banned, perhaps this would be a good way to continue.
Agreed. This was just an example. I mean I would leave negative trust only to users (spammers or not) who behave untruthfully.