I think that the manga is pretty good and I'm really disappointed in Seven Seas letting this one go because of a couple of people bitch about it.
Well, their loss.
Though, I think that Aoki is pretty stupid. The girl has hickeys on her neck...they are from her 'guardian' who is having a hard time raising her. As her teacher he should've said SOMETHING to the heads of the school.
Even if they couldn't do anything they can, at least, keep a paper trail on her just in case to keep an eye out on her.