Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
It's a special incentive I added this month in an update post. If people didn't cause any issues by not showing up at the scheduled time without notice or not responding to messages for no reason or such, they'd get 1-2 extra prizes from the list. Though I may keep that incentive in the future.