This sort of thing happens every week these days.
Hell, I recorded a fight in high school and that was years ago.
Of course, the fight I recorded was pretty piss weak and it was a 1 v 1. No one was seriously injured... Not even a black eye.
Funnily enough (and this goes to show how things change and how different our countries are) I was actually given an award at an end-of-year assembly for 'Best use of technology' by a group of teachers in front of the other students.

Like I said, though, no one was injured in the fight and it was a stupid fight over a girl... One of the guys diddlyed the girl, the other took offence at that because he was keen on her etc etc.
It is a different story to cause serious injury with the intent of causing further humiliation. Not to mention the fact that it is the height of stupidity to commit a crime and FILM yourself doing it.
On the positive side, as this sort of behaviour is becoming more and more popular the penalties for such behaivour are becoming more severe. My story is evidence of that... Within 5 years it has gone from being an 'end-of-year joke' to a criminal conviction.
Things like this will always continue to come to light... technology has permeated every facet of our lives and drives its roots deeper with the birth of every new generation.