Last week I sent in a request for the BTS/BitUSD market to be listed on both BTS and BitUSD.
Currently BTS/BitUSD volume only counts towards BitUSD.
My rationale was that if volume was significant, it wouldn't make much sense to leave it out of either one.
It might be "double-counting" volume but CMC did agree to list shares+assets on the main page, which does the same thing to market cap.