Not in public schools in the British sense. I assume it varies in public schools in the American sense, and I am guessing violence sufficient to render someone unrecognisable is pretty rare even in the worst of them.

Than killing with bare hands or a rock, which I believe is still pretty uncommon in schools.

GP didn't talk about killing

Extreme violence then? With rocks, clubs of bare hands? I was responding to "render other humans unrecognizable with a rock" which I am pretty sure is uncommon in schools.

Render unrecognizable? Yeah, I guess that could be survivable, but it's definitely lethal intent.

That's possible with just a well placed punch to the nose or to one of the eyes. I've seen and done that, in public schools.

Uh... sure, maybe during the initial swelling. But that's temporarily rendered unrecognizable.

If you caused enough damage such that someone could not later be recognized, I wonder why you are not in prison.