Pretty much my guess. It's possible the teacher and the police dramatically overreacted and are at fault. It's more likely, in my estimation, that the kid was behaving like a rebellious little snot and got introduced to some adult consequences.
I was ever only threatened with arrest once, and that was because I cracked a water fountain with a dude's face. In self defense, of course, but the school still had a dim view of it despite the bloody nose and busted lip he and his friends gave me slightly before that. I was usually pretty good at talking my way out of trouble. Avoided quite a few detentions that way. I even managed to get off scott-free after threatening to snap Jed Koblisch's neck right in front of the principal of my high school. It helped that neither of us liked that little punk and that even the principal had to admit that someone needed to knock his block off.