Messages sent through the RMail service should not be flagged as spam any more than a regular email.  In fact, through many of our partnerships, RMail is actively becoming ‘white-listed’ with many of the large corporate ISPs, Managed Service Providers and Email Service Providers. If a message is rejected by a spam filter outright, the Registered Receipt email may indicate “Delivery Failure.” If a message is delivered but classified as spam by a local spam filter, the Registered Receipt email may indicate “Delivered to Mail Server.” In this case, the receipt allows the sender to retain proof of delivery for that email.  This is important if the sender needs evidence that they fulfilled their requirement to send a notification.