Well said, Golfer. A rapid onset of high G without knowing it's coming and no anti-G equipment can result in GLOC incapacitation.
Very true..
I was on the phone this afternoon with a friend who raced a P-51 and performed at airshows. He mentioned the Voodoo incident and stated that at 450 mph, the P-51 is heavily trimmed nose down to offset the tendency of the nose to come up. The loss of a trim tab will induce a sudden pitch up, sufficient to over-stress the airframe and induce GLOC. It's especially problematic for a pilot in his mid 70s, who will not have the conditioning of a 30-year old F-15 pilot. Moreover, you have absolutely no time to prepare yourself for the onset of g loading. A younger, more fit pilot may have not GLOC'd, but it's not likely. Hannah was young and in pretty good shape and he was out for more than long enough to have crashed.
I'll wager every P-51 racer will have its tab hinges inspected immediately. Indeed, perhaps the structure needs to be reinforced for racing. I would not be surprised is mandatory inspections were ordered for all racers in the unlimited class.
I've heard many comments made in the media about how the pilot managed to avoid the crowd... He didn't avoid anything, he was out like a light. It was simply good fortune or maybe Angels that steered the Mustang away from the general grandstand.