Oh, I believe that the traffic indicated in our "Traffic Sources" does not strictly say that the the hubber himself is visiting your hubs. I'm not so sure about it, but that's the way I understand it.
Anyway, if my guess is right, you get traffic when people get redirected from a different hubber's hub to your hub such as clicking on the "related hubs".
This type of traffic is and placed under the name of the hubber (i.e. name.hubpages.com). :)