I don't have a source (just browsing twitter, reddit, etc), but i keep hearing people say that it sounds like a reform school, but the cast is there because of society failing them, and not the character's faults at all that they are there.
If this is true, it makes sense with the theme.
EDIT= Found a source
Post 1: https://twitter.com/avestal/status/563792686549712896
Post 2: https://twitter.com/avestal/status/563792925180444672
Post 3: https://twitter.com/avestal/status/563793075139407872
Andrew Vestal himself is guessing and making an assumption, and his entire tweets rely on it.
We'll have to wait to see what Famitsu says next week. It should have a lot of information about the entire cast.
I definitely don't think it's a reform school. If it was, they would have made that detail more apparent. Such schools usually have run-down standard (sailor or blazer) uniforms too, because they're cheap. Not the fancy uniforms the school kids appear to wear in the trailer.
I don't think it's a reform school, but a regular high school.
http://www.neogaf.com/forum/showpost.php?p=150867572&postcount=4714
Seeing your explanation and the actual wording for myself, yeah, this is not a reform school.