Terry,
Buying stuff sight unseen from folks you do not personally know can be risky, especially when someone joins a group like TG with the intent to deceive. I appreciate the effort you and Rob put into ideas and procedures designed to protect the general membership. In addition to a fee, one time or annual, how about asking the folks who want to be pre-approved to provide some form of personal ID, like a drivers license number. Doesn't guarantee success, but adds one more hurdle for the less than honest to overcome.