have you ever worked with young children? the method you propose will lead to bullying and fights. there needs to be some moderation.
There has long been this subculture of actively encouraging bullying amongst children in order to "weed out the weak", and it's disgusting every time it's suggested.
In my experience it's usually a rationalisation by those who wished to do the thing already, but now even more than apathy, there's a moral obligation to bully people, which is quite appealing if you want to do those things.