Board Thread:General Discussion/@comment-28522425-20170408122224/@comment-14909251-20170416222215

Ozpin may have known everything, but he isn't the type to reveal every little detail he knows about someone. While Ozpin could have very easily known, it is possible the leadership of the White Fang was not public information or at least not widely-publicized information. The fact her father is the leader of Menagerie is probably more of an issue in terms of people somehow not knowing. No reason that information wouldn't be well-known and her having the same last name is definitely one of those things that could out her.