But on the other hand, retaliatory feedback or the threat of it, discredits the entire feedback system.

In an earlier post you talked about a deal where the buyer returned for a refund and then left you negative feedback which said you did refund but complained that you used a Western Union MO which they said was hard to cash.

You said you felt you had the right to leave negative feedback because the buyer was so unreasonable.

The Feedback that you left was:

This person is a NIGHTMARE Not happy even with REFUND Just AWFUL THE WORST F-

Do you really think that was appropriate. the suggestion of your earlier post was that you had no problem with the buyer returning for a refund (interestingly your auction makes no mention of a return policy, but your Square Trade seal says that you "Disclose pricing, shipping and return policies in a clear and accurate manner").

Your post seems to suggest that the only reason you felt a negative was appropriate was because he negged you. You referred to this as a NIGHTMARE.

Perhaps there was more to this than you disclosed. If not, I think is an abuse of the Feedback process. While feedback should accurately reflect your satisfaction with the transaction, it should not be based on the feedback left for you, because that makes all feedback meaningless.