It is a messy situation for Stoxpoker since they lent him their credibility and he then used that credibility to scam people and find people to scam among their customers.
And it is not just Stoxpoker. How about DC, http://www.deucescracked.com/coaching
where the coaches advertise on the site. Are they in any way responsible if people get scammed by a coach there? If I was hiring a coach there I would think I would get a DC coach with DC taking responsibility. If that isn't the case, where is that explained?
I think the sites would be well served to think about where their liability starts and ends. Unlike the poker sites themselves they are situated in countries where it is easy to seek compensation via the juridical system.