:( I had it right the first time. It's getting too late to submit patches.

Author: quentusrex

interface/web/mail/form/mail_user_filter.tform.php

@@ -42,7 +42,7 @@
 $form["db_history"]		= "no";
 $form["tab_default"]	= "filter";
 $form["list_default"]	= "mail_user_filter_list.php";
-$form["auth"]			= 'yes'; // yes / no
+$form["auth"]			= 'no'; // yes / no
 
 $form["auth_preset"]["userid"]  = 0; // 0 = id of the user, > 0 id must match with id of current user
 $form["auth_preset"]["groupid"] = 0; // 0 = default groupid of the user, > 0 id must match with groupid of current user