Except obvious things like hiring newbie users
Why does hiring newbie users indicate that the signature campaign is a scam?
Are you indicting the Newbies as being less trust worthy? Or are you indicting the Campaign Manager as more willing to scam all users if Newbies are involved.
You sound a bit elitist! We should be helping Newbies, not cutting them down.
I would think the most obvious indicator that a signature campaign is a scam is when you don't receive your payment after the campaign period has concluded!