Permission checks
Email permission is recorded before any follow-up email is considered.
Unsubscribed customers are never sent follow-up emails.
Customers marked with a do-not-email rule are never sent follow-up emails.
Customers marked as service messages only are never sent follow-up emails.
Customers with unknown email permission are never sent follow-up emails.
Hard bounces stop all follow-up emails.
Spam complaints stop all follow-up emails.