The video just shows an example of bad, or inexperienced, riding and luckily it didn't hurt anyone. It is a clear risk at the track, that someone will do something in error and you will pay. This is something everyone doing rounds at the track should understand and accept. You risk being hurt and it is not even going to be your fault.
That said, it is a very rewarding experience to go to a track day and play with your bike in a fairly safe environment and I recommend it to everyone.
But I think it is important to note that there is a clear difference between racing and trackdays, we can not have people acting like everything goes and it is OK because it is racing. It is not, it is a trackday and we are all here to have fun, and it is funnier if you are faster than your mate, but not if you put other riders at risk.
And even in racing, not everything goes.
Again, the example just shows a normal incident and the R1 rider would be recommended to take a few sessions with a masterrider/instructor and then allowed to ride free again after showing that he understands how to behave at the track. No biggie...