It's still a good point though (other than the scamming part). If you don't trust someone's judgement, why would you apply to join a campaign managed by that someone?

I'd say anyone who thinks that way ("will this affect my signature earnings if I make this exclusion") shouldn't be allowed anywhere near the trust system but reality is probably the opposite - most of the trust lists are likely built on various backscratchings and bootlickings.