Instead of blaming member about how they trust other members try to update your forums feature and increase its security! Your forum is full of scammers. I can tell for sure that almost 80% of your members are scammers and you need to do something about that!
Thing is, you shouldn't trust members, and if you do, then it should be someone with extensive and positive trade history.
Stop Blaming the members about how they trust other members. They trust on your forum when they accept to have a deal with your members! You keep asking to use escrow but how about the fees? Who is going to cover it? How much profit is on a deal that you expect us to use escrow and pay its fee?
Stop blaming forum because you trusted someone that wasn't proven trustworthy by other members. You trusted newbie account with no proven trade history. If you can't afford escrow fees (that are usually in the 1-2% range) and person you want to have business with doesn't have good trade history, simply don't do it. No one is forcing you to trade. And if you decide to do it anyway, accept the risk and consequences of your actions.
Since your are on
bitcointalk forum, I guess you know that bitcoin is about personal responsibility. So be responsible and don't blame the others for your mistakes.