I wanted to revisit this and found the following on Ebay:
Losing feedback privileges:
When a buyer does not respond to an unpaid item notification and the seller issues an unpaid item strike against them, the buyer can still leave a feedback comment, but the feedback rating they leave for the transaction WILL NOT APPEAR AND WILL NOT COUNT TOWARD THE SELLER'S FEEDBACK SCORE.
An ebay administrative note will appear under the feedback comment, explaining the the member did not participate in the unpaid item process.
Buyers should always respond to disputes opened within the unpaid item process.If you have resolved the situation outside of this process (for example, by making a payment by phone or e-mail), please go back to the dispute console to enter a comment. Otherwise, you may lose your feedback privileges for that transacation.
NOTE: When an UNPAID ITEM DISPUTE is closed automatically, the BUYER WILL LOSE FEEDBACK PRIVILEGES IMMEDIATELY. This happens when the buyer is no longer a registered user of ebay at the time of the unpaid item filing or is from a country to which the seller has indicated they will not ship.