Sorry, there has been a misunderstanding. My first comment to which you replied could be rephrased as "There is a big arb opportunity which they are not exploiting, and it is interesting that they are not doing it." The continued existence of the arb opportunity is a public fact, which is why I was a bit baffled that it would be questioned. It was not clear to me at first that you believed I had claimed that Mt. Gox was not participating in the market at all.
