In January my company had a subscriber purge by getting rid of lots of subscribers we no longer email/unsubscribed long ago.
Most of our data is held primarily in a SAS platform and we receive regular extracts for email campaigns.
We had to make sure we never receive purged subscribers from the SAS platform again, in case we accidentally re-add them as a Subscriber.
Unfortunately, some of them have slipped through the net.
However, we noticed that when our automation script runs, the number of records decreases after it is transferred from a large (non-sendable) data extension to a (sendable) data extension.
When I looked into why this was, it seemed it was recognising that some of the people included had previously been purged via Contact Delete, and it was excluding them from being in the data extension.
I can't find any literature about the Contact Delete function - can anyone confirm that SFMC recognises subscribers we have deleted, and acts accordingly to stop them being re-used?