I like the idea because it is an online-version of the Prisoner's Dilemma.
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Now, this idea can't work, beyond just the failings due to the prisoner's dilemma.
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So, in short, this won't work.
You like the idea because it doesn't work?
Appeal to the mods if you want real change.
That's not how it works around here, and it's not the mods fault. They simply don't have the power to instate anything like suggested in this thread.
EDIT: Actually I suppose they do. If someone violates the policy they could ban them, but that's a tough sell. It's not against any explicit site policy and short of bragging about your child porn chances are you won't get banned.
EDIT 2: Would you apply this to all sections or just the US side? There doesn't seem to be a lot of trouble on the PCE side. Honestly, I don't care if someone has no posts and no rep and lists something for sale. I can just ignore it and not buy what they've got if I don't think it's worth it.