Since Liebherr took the time to properly engineer this stunt; I'll say it was more a smooth and gutsy operator. However; if it was yokel doing something similar with a 6-pack or two under his belt, then I would classify it as crazy.
I'd say, Stupid, but what do I know. Can't imagine how that would help sales either.
It certainly is a display of power and costs overkill. If the hydraulics and build are strong enough to do that how would you use it to dig? Seems to me if you purchased a machine that big to do real heavy work you would be constantly tipping the machine over. Just sayin. Then again maybe I missed the point for the video. Maybe I'm crazy.