Centre stands....for better or worse.

[Grahamm]

How could it be so easy for that to go so wrong?  :\

Looking at it carefully, I'd say that what happens is that, as he starts to put it on the centre stand, his left hand pushes the left handlebar slightly forward.

Then, when it doesn't lift cleanly onto the stand, it rolls forward, the front wheel is twisted to the right and the momentum of the bike is away from him and there's simply no way for him to get the centre of gravity back before it goes over