On another forum I use they recently implemented this rule and it has gone down well with less scam threads popping up, detailingworld also do it too
Every for sale thread should have a pic of the item selling with a pic of the users username along with it, no catalogue/internet pics, proper pics of the items so people can see what they are getting before they buy
Yes its not going to stop all the dodgy dealers however it would most definately help
Threads missing the pics would be locked and deleted until the user complys with the rule
Also clear prices inc postage should be displayed to avoid confusion too
Anyhow just a suggestion
For Sale Section
Threaded Mode