If customer has an account with their real email address, and they use Apple sign in with masked email address to create another account on our site, what happens when customers click on 'unsubscribe' from the marketing emails they receive in their inbox.
Once a user disables forwarding or decides to stop using SIWA with an app, the emails will start to bounce.
#1, Having an account with a real email address is separate from the account they create when they use @privaterelay.appleid.com emails in SIWA. They will be completely separate accounts from the perspective of the developer.
#2, Turning off the flow of emails in iOS settings is not the same as clicking on an embedded link in email content to "Unsubscribe".
#3, Assuming that the "Unsubscribe" link embedded in the email is going to unsubscribe the @privaterelay.appleid.com email, then the developer would receive an unsubscribe email to whatever list processor they have and it would appear to be from the @privaterelay.appleid.com email address.
#4, The developer should remove the privaterelay email address from their list of outbound email contacts on their email server.
