First off,,, the father is nuts,,, totally nuts. I agree that he was not in control or that he could re-gain control if needed,,,, crazy!!!
But on the other hand, I think we protect our kids toooo much nowadays,,, well some of do. We need to let them loose a bit more often, but that takes prior training on the parents first of all and then the right kind of up-bringing from the start. For many of us thinking about a 6 year old running a dirt bike or sno-mobile on their own?? we cringe!! but then those of us who do have sheltered our kids more than some others and the kids are not ready to handle things properly.
For others, the kids have learned early on the fear of hurt, the fact that if you don't put your foot down on the stairs right you get to feel what a tumble feels like. These kids operate on a different program than some others, but it's not for all kids, or parents for that matter.
I didn't put a tight rein on my kids when they grew up,,, on the other hand I would not have done what was seen on the video,,, that's nuts!!! My grandkids are being raised more of less the same, one grandson ran a 48" lawn mower at age 5, he sat on the edge of the seat to get at the controls and nobody was allowed in the yard when he was busy. Today @ 10 years old,,, hey it's his birthday today,,,,,that young fella will outclass many grown-ups with common knowledge, what's safe and what is not so safe. Has to do with his character and his upbringing and for sure,,, different strokes for different folks.
But NO!!! my sons would not have done this either.