Toro,
Having done a few SIBs recently, it's not the Safety course teaching this. When the board first sits down and takes over from the ISB, the Safety Center rep gives you a lot of guidance. What I've been told on the last two boards I was on (Pilot member on one, IO on the other) was exactly what was stated above. Don't give priviledge to everyone, have specific documentable reasons why you granted it when you do, and not to grant it unless requested.
BL: Ask for priviledge up front. If denied, I'd recommend going straight to a lawyer...
Droopy