Unsubscribed Prospects can be tricky to deal with.
On the one hand they’re not considered mailable, so they won’t be taking up any of your precious allowance of Prospects, but on the other hand it’s always frustrating having a chunk of your database essentially going to waste. To compound the issue, the development of mail security technologies has given rise to email scanning tools that virtually “click” every link in an email to test their validity during the spam detection process. The upshot of these technologies is that Marketing Automation platforms such as Salesforce Marketing Cloud Account Engagement (MCAE) can register a link “click” from a Prospect before the email has even arrived in their actual inbox, as the spam detection software has provided a false positive.
In relation to unsubscribed Prospects, this can mean that your Prospects with more sophisticated email security software in place can actually register automated “clicks” on your unsubscribe links and therefore their Prospect record can be unsubscribed without the actual person ever being aware of it. The replacement of one-click unsubscribes in the email footer with links to preference centres has done much to counteract this issue, but it unfortunately cannot revert previously affected Prospects.
So, we have a situation (that is not uncommon) where portions of your unsubscribed Prospects are not actually aware that they ever unsubscribed. This obviously presents issues whereby these people may fill out your MCAE forms to register for events and will not receive any non-operational communications that they would usually receive by email, such as confirmations, reminders and recaps – so how can we make them aware that they’re unsubscribed?
For this, we can turn to a well-kept secret setting that seems to be rarely enabled during implementation – the Resubscribe Pathway!

