It doesn't work that way. The GNU mailman robot responds to "unsubscribe" commands if you send them to the "-request" suffixed mail alias; in this case users-request@lists.roundcube.net, ratherthan the plain mailing list address users@lists.roundcube.net.
NOTE TO LIST: I would have sent this privately to Rhy Thornton. But you chose to assert this header:
Reply-To: Roundcube Users mailing list users@lists.roundcube.net
So when I hit "reply to" (rather than the usual "reply all"), I got above in my "To" box instead of Rhy's address. And by golly, I'm not going to go to the trouble of replacing that address. Too much work! I'm going to do what you're telling me you want me to do via this header, which is saying to me, "please reply to the list, and not to the original sender, regardless of the subject matter!"
Should you ever choose to get a clue about mailing list configuration one of these years, google for "reply-to munging considered harmful".
On 18.10.2013 14:10, Rhy Thornton wrote: