I don't know when a transaction is made how long each side has the ability to post feedback or if there even is a time limit.
I am wondering what would be improper or even a drawback if feedback by either or both parties (Seller and/or Buyer) has not been left within 30 days after the transaction that a POSITIVE feedback be left automatically for the individual(s) that have not received feedback yet.
The feedback automatically left could even be marked Automated Feedback (or something of that nature) if it needed to be.
If the option to change the feedback was left available on the automated feedback the person the automated feedback was inserted for could change it if they desired, however, they should not be able to delete the feedback. I feel like many times feedback is not left just because the Seller or Buyer doesn't want to bother with leaving it. If the reason is something similar to this how many would go in and change the automated feedback.
Automated feedback would also take care of showing a sale had been made. They allow imported feedback from other website and to me the eBid automated feedback would be more valuable to everyone.