SMG should display a warning banner and send an email notification to notify the administrator about license expiration. The banner should start 30 days prior to expiration and be displayed at the top of the System Administration interface until the license is renewed or the banner is acknowledged. An email should be sent 30 days prior to expiration and at regular intervals after that.
The current procedure is that SMG just silently stops filtering and passes email without doing anything. This puts the organization using SMG at risk and is a horrible failure. License expiration notification is very important!