Alright, this might not help but it's a start. I've posted my lists of dead beats in the Admin's section, sorry, you guys can't go there. But if you have doubts about trading with someone you can ask a Moderator or Administrator if the person is on the list.
I know it wouldn't have helped with the last episode since everybody traded with a first time "cute, helpless, kid" but I know some of the guys on the list from the past are in business on PaleoPlanet and other sites.
And feel free to let us know about any other trades that go south with a PM.