They didnt know who was causing it or why. Blocking a persons ability to contact emergency services, by DoSing their phone can be devastating.

Right, but did anyones attempts to contact emergency services get affected in this case?

I'm guessing not.

No matter how you paint it, this was probably rather excessive on the part of the police.

And on the part of who called the police in the first place. In my experience teachers and school management are just too paranoid/neurotic and will escalate everything so they can't be blamed.

It might be legal for them to call the cops, but it still does not absolve them from moral responsibility for their actions. Including all the distress it would cause the child's family, and the likely ongoing PTSD from the incident.

>Blocking a persons ability to contact emergency services

Looks like they still can call the “emergency” given the police was there after.

40+ years ago I did some dumb things in school as well. But in all cases I got punished by my father. Not because I hurt somebody, but because I wasted a lot of people's time who had to deal with consequences from my actions. I didn't respect other people and their time and it was enough for my father to punish me. And he had every right to do so.

When I was a teacher some time ago some kids did a dumb things as well – they "hacked" schools' computers by putting some really sticky putty under keyboard keys. I wasn't allowed to punish these kids by ordering to clean it after themselves and parents agreed to pay for a new keyboards after weeks of "discussions" with lawyers involved.