User blog comment:WeissSchnee/Yellow's Trailer Music/@comment-86.181.71.68-20130602105424

I don't know, maybe they start as enemies or something first? I think Yang might have been trying to hunt her down.

Remember that in Blake's trailer, she was infiltrating and destroying carriges with Weiss' insignia on them, and then she shows reluctance and goes "rouge" and leaves Adam.

Maybe Yang was hired to track her down again? Although I have no idea if it's to make her pay, bring her back or join their team. Maybe she was hired by Weiss? Who knows :)