User blog comment:Zathronas/Analysis by an author: Volume 2 episode 2/@comment-3387274-20140802103234

according to an interview, Cinder is just a bit too old to be a student, but not that much older, and clearly can pretend to be one. Also, she already recognises Ruby as the girl she nearly burned 18 episodes ago.

speculation wise, it seems apparent that Qrow's warning was about some kind of threat, almost certainly an attack, hence Ironwood bringing an army to protect Vale. I suspect, based on Ozpin's wish to be tactful and not give the wrong impression, the attacker would be the White Fang. My reasoning is that they are the only opponent we yet know about that you don't want to threaten until they are openly threatening you. being paranoid about faunus would heighten the discrimination that led to the WF forming in the first place, and thus makes the situation worse. It could be another yet unknown thing, but I doubt that, since there seems to be no other foreshadowing for such a thing.