**UPDATE**I have viewed the help file and found the info. For those interested, it says
Use calendar to set Advisory message: Enabling this option adds text (based on your calendar entries) to your Dynamic Status to indicate your calendar status. Typically, Advisory messages reflect the following calendar-related information:
- You are currently in a meeting, busy, or out of the office until a particular time
- You are scheduled to be in a meeting, busy, or out of the office at a particular time
You are scheduled to be in a meeting, busy, or out of the office at a particular time
If an appointment is marked as Tentative, the Advisory message includes this information too.
...so yeah, it appears to only enable/disable the display of the calendar event on the UCA Client.

Thanks,
-Iron