Uh... that story sounds very strange. A magical double-bass? Uh.. it just sounds very very strange. It also sounds like someone TRIED to copy the Harry Potter books.
Although, this story sounds very one-sided. We don't learn anything at all, really, about the story- only what they thought sounded like Harry Potter.
What's her facial marking? We don't know! What's her air-sport like? We don't know. We don't even know anything about this Tanya Grotter besides her name and that she's magical. She could be a witch who travels the universe- that's nothing like Harry Potter.
What I'm trying to say is- It could be more different from Potter than we think. News can mislead us like that.
It saddens me.