This is one of the most interesting threads I have read for ages! I have to admit the footage at first looks damning, but I really think we have all been a little too hasty in our judgement. Experience must tell you that there are so many factors that could cause this type of loss of control, ranging from an inexperienced pilot showing off, to an aircraft malfunction. One thing that does spring to mind is the possibility of control interference. I have been piloting a helicopter on short finals to a landing site, when my own bl00dy co-pilot got his foot stuck on one of the pedals, so I wouldnt rule out the idea of a heli unaware passenger doing the same. Although no-where near as dramatic as this, it could have been. Is it possible that dual controls were fitted and there was the chance someone in the front turned round to take a pic or speak to the person behind them, and jammed their foot forward inadvertently? Maybe, maybe not, but we should not be so quick to judge just yet, as reality can often be very different from first appearances.
Still - gotta admit though, I would love to hear the pilots story!