They do a pretty good job mixing, so it would take someone a lot of effort to track anything like that down. If we did have the address they were mining into, assuming they are mining at all, we could figure out roughly what their actual hash power is, which would be the most interesting piece of information. It would go a long way to either legitimize this or show it for a ponzi. At this point I don't think anyone would really care. Lots of people have gone past break-even here, which is more than can be said for most cloud mining ventures.