With that many kids, at those impressionable ages, I'd say there's a limited but real chance they may have created a "Joker" level villian somewhere in that bunch.
What scares me about it is that these kids have likely gotten used to juvenile detention (and detention in general), which'll lead them to view it more lax.
Adding to that the time they lost outside of the school system, the social stigma that goes along with having been to "jail" and you've got yourself more a more explosive cocktail than anything described in the anarchists cookbook.
If you're socially sidelined and have no options for a career, crime is enticing. Especially since you've been stamped a criminal allready, and you've been locked up (yes, they were aquitted, but they won't realize that, and their peers won't either).
Assuming they just took problem kids across the whole spectrum, assuming 500 non problem kids, you have 3500 problem kids. A rough guess of mine would be that 1-2% are too smart for school kids that cause trouble out of sheer boredom. So you've got 70 bored hacker type kids that suddenly have someone who's mistreated them, and I'd want to get back at them. A couple of them proably took the frugal coping mechanism of sociopathy.
If your school system gets kids to come to school armed, prepared to kill, how the hell will that play out?
