Avoid Mailing List email being ignored as Spam.
A common problem is individual email accounts being hacked, and spam or virus links being sent to every contact in the address book.
This includes your Mailing List.
The hacker typically sends a message to emails from the Contacts list, using either the To: or CC: line.
Our system assumes that any email with more than 2 addresses in the To: or CC: lines is spam sent from a hacked account. This is assumed since all new emails are sent only to the Mailing List and not to individual users.
When this happens, the message is silently stopped and not delivered.