Do you want to be the brave one who dismisses something that later kills or injures others? I'd rather be safe than sorry
Those who will trade liberty for safety will have neither. (Ben Franklin)
Misdimeander prank, yes. Terrorist threat, no.
When I was an inquisitive mind in high school and in college, my buddies and I made and detonated many such harmless devices. It is actually part of the engineering learning process. It is also how the US government gets its own explosives experts.
Americans and their "leaders" seem completely incapable of measured and appropriate response.
I would rather they treat this for the prank it is rather than an opportunity to permanently jail yet another young American. That would be the adult response. The "rather be safe than sorry" stance is a sheild for the uniformed and weak, not for those who understand youth who seek "out of band" knowledge.