Windsurfing SA is the organising body for this event, because as a sporting association, it covers itself with public liability insurance.
GPS Speed Sailing is dangerous (as is wave and slalom sailing) - it is wise for the organising body to be structured this way.
The benefit of this is that with everyone at an event covered there is no risk that gaps can suddenly appear in the cover if a claim is made.
This insurance cover for an individual comes with their state association membership.
It is also a good thing to be supporting your state windsurfing association.

Refer:
www.windsurfing.org/insurance.htmSo yes we do require each entrant to be a current financial member of Windsurfing SA, or their own state's windsurfing association.
No discounted half-year memberships...sorry Red.
Here's a list of current AWA 2012/13 members:
www.windsurfing.org/files/info/AWA_Members.pdf