Anyone who knowingly participates in a scam project should be punished at least with a signature ban, and that service should be banned from the forum - everything else is completely wrong and sends the wrong message to all who are on the forum and who are yet to become members.
If we are meddling with the "scams are not moderated" policy, that shouldn't be exclusive only for members who participated in scam projects. Any members who stole something, scammed in a trade, didn't repay a loan, etc. should be treated in the same way. They are obviously not trustworthy and shouldn't be allowed to advertise anything.