The GPS HW is always available -- if 911 wants your location, they will get it. When you "turn off" GPS, all you do is stop all applications from getting it. Except 911.
And when I say GPS -- your phone doesn't use GPS that much. It locates you via the cell towers, and you can't avoid that. So permission is turned on/off for your *location*, not necessarily from GPS.
I wonder how evil Google will have to get to start to leave a bad taste in everyone's mouth?