Pucker factor HIGH.
That happened a while ago. Truck was basically hanging by only the safety chains. The coupler on the trailer was NOT on the ball anymore. Folks were very lucky. Technical and sketchy rescue.
I have been over that gorge more times than I can count, and have stopped at the little visitor center/info kiosk there a time or two. It's very narrow (blink and you'll miss it at 80mph on I-84), but very deep. That would have been a long drop, had things let go.