OUCH
They should have had to sign a waiver to get into the facility. My experience with SCCA-sanctioned events is that they're usually pretty good at enforcing this. Had it been an independent club there could be a fair chance that they wouldn't have signed, but it's a reasonable assumption that they did sign.
I vote it is not the course designer's fault. I've autocrossed plenty, and in most of our courses if you cross the finish trap at WOT then hit the clutch instead of the brake...guess what, anything in your path is getting slammed. The driver who crashed the GT3 apparently normally drives an automatic 'Vette, so the clutch pedal was foreign to him. Autocrossing isn't risk free, and I'll continue to do it. But on Sunday I'll park just a bit further from the cones
You're right. The GT3 should be at a race track and not driving around in a parking lot. It's easy to see the type of cars generally found at autoX events. And never let anyone drive your car, unless you really wouldn't care if it's totalled.
In many states, a release will not protect someone from future acts of negligence, which are not forseeable. It is different than an inherent risk of the sport, like debris from a race track flying up and hitting your eye. Ya, I predict someone is gonna pay for their 'play.'