Here's what I will say in defense of the authorities: if it were a bomb, the kid might have had a trigger mechanism hidden on his person. Which I'm sure is why they put him in hand cuffs until they could either make sure it was not a bomb, or they could search his person. Because he's a minor, searching his person becomes a little more problematic, and time consuming, because I suspect they would need a guardian present. So although the cuffs seem excessive, it was done for a reason.
Also, it's right that the teachers did not try to handle this on their own. They're just not trained for this sort of thing, and therefor, they could have increased the danger if it were real, by meddling.
I think where the authorities failed was in their reluctance to "stand down" once they saw that there was no bomb, and therefor no danger. Arresting and "investigating" the kid was stupid. And so are all these idiotic complaints about the president wanting to assuage the trauma to the kid by doing something special (and public) for him. Let's face it, we all know how cruel kids can be, and having them see this kid cuffed and treated like a criminal for being of Persian decent is an invitation for all kinds of abuse. Abuse that Obama may have mitigated by making the kid out to be something special, in public.
So hopefully the kid will be fine. No harm will have been done. And this will all blow over just as it should.