Isn't it time to make positive feedback a default after a few weeks.
The biggest problem I see on here is the amount of zero feedback buyers who buy and then disapear.
If feedback were posted as say " Great Transaction Thanks " It would give buyers the chance
to leave their own feedback before it is left for them.
Just put something on the website that states, " If You Do Not Leave Feedback Within 6 Weeks Then The Default Will Be Positive "
Regards Jack