Unsubscribed Duplicates
From EtelligentWiki
If there are several contact records with the same email address in your installation, as long as one of them is not Unsubscribed (remove=1 and badAddress=0) or marked as a Bad Address (remove=1 and badAddress=1), then Etelligent will still be able to email them.
When Sending, Etelligent pulls out all the contact records included in the selected Filter, groups them by email address and ignores all but the record with the highest contact_ID which it will send an email to.
