I would have advised the kid not to turn around and punch Zimmerman and then jump on top of him. I would have advised him that was against the law. Zimmerman, as far as we know, broke no laws, he was only stupid.
Reiterating: Poor judgment in and of itself is not illegal. Poor judgment that results in injury or death can be - that's why we have laws on the books that consider negligence.
Did the person act in such a way those actions might reasonably result in injury or death?
Did Zimmerman not consider that searching for a criminal (which I believe was already decided in his mind) might result in a confrontation?
Did he not consider that if a confrontation occurred, he might have to draw the weapon he carried?
Did he not consider that drawing that weapon might result in death be it the "criminal's", his, or a bystander/occupant of a nearby residence?
Any evidence that he did so?