If you've received a Blacklist Notification this is because it was determined that you were the most recently active Support contact for the Marketo subscription.
When the Privacy team is notified of a blacklist issue regarding one of our customers we look at the most recent case that the customer has open with our Support team. We follow this process to ensure that the notice goes to an active and engaged user of Marketo. Typically the most recent Support contact is the right person to send these blacklist notifications.
This notification process is mostly automated so we can't identify a specific recipient of the alert, they will always go to the person who most recently submitted a Support case. If no Support case has ever been submitted a member of Marketo's Privacy Team will chose the contact manually.