In reply to Paul.

If both plug-ins did the same thing to each other, the response should be the same.

I think the response was the same: both plugin authors were told that they needed to remove code targeting the other. The PO author complied; the WPSS author didn't & won't (and has made it very clear that he doesn't intend to because he considers the PO plugin to be "malware" -- but that is his opinion and obviously not shared by the WP plugin team)