User blog comment:PuffDragon/On the Red Rose lyrics/@comment-7713314-20130403160140

Someone has to be literal, otherwise we miss potential ideas. Even if they come about by process of elimination.

But you're right. If anything, the lyrics are probably trying to give hints on the characters themselves. For Weiss it's easy to make that assumption, given her apparent(in our eyes anyway) position. Ruby could be trying to find something, which leads her to the 'institute' the show takes place in. Blake's line may just allude to her less than noble origins and being a thief.