Would one of the devs be able to /dev/null the mail invitations from LinkedIn that make the mailing lists? There are some simple lines in the headers that would enable the mail to flicked either globally by the mail server, or presumably by the list software.
Received: from maild-bd.linkedin.com ([216.52.242.161]:54466)
by lily.knams.wikimedia.org with esmtp (Exim 4.69)
X-LinkedIn-Template: invite_guest_59
X-LinkedIn-Class: INVITE-GUEST
X-LinkedIn-fbl: s-v9FvDjY93SMCw2LCDeH--JPOI4MtdaGj1gFFEDerfK1tZt2hQCmNl3
Version: unspecified
Severity: normal