Generally, you can avoid retalitory feedback by just
not leaving feedback. The
other way is to "snipe" the feedback at the 60 day limit of when you can leave
feedback (or so I've been told.)
Be careful. I've never had cuase to do this, so I am not sure, but I've
been told that if you know the auction number (for want of the better
term) yuo can leave feedback after the 60 day limit. So sniping may not
prevent retaliation.
-tony