That first one is the famous Tracy roll from a few years back. Watch it again and watch the spotter, and the front tires closely. That wasn't the spotters fault, it was the driver not doing what the spotter what telling them to do, and continuing to drive far after the truck got into trouble. Paying more attention or simply hitting the brakes would have saved a lot of $$$ there.

The second one...I've spotted many people from that exact spot, the difference is I didn't spot them into that dumb line. Normally that spot is reasonably safe, if you take the correct line. Bad choice on that one.

Bottom line is, if you're gonna have someone spot for you, make sure you trust their abilities, and do what they tell you to. They can sometimes see what you can't see or feel. If you're spotting for someone else, make sure you've got an escape route.

Dallas