Cristian Consonni, 01/08/2014 00:18:
(If somebody can make a case for "Discard" over "Reject" please do so).
"Discard" is probably unneeded: the spammers will receive confirmation that the email address exists, but there's no proof they need to know (they may be targeting mailman installs specifically). While humans get confused by not receiving any response to their rejected messages.
Nemo