How can a Bitcoin consumer and a Bitcoin seller mediate disputes?
I'm a mediator and this is an interesting subject. In the conventional world it's seller beware, as the customer can either not pay at all, or charge back a credit card. In the case of Bitcoin, the situation is reversed, and payment once made is gone. I don't think that the issue is with the bias of the mediator, most are neutral, but I do think that a mediator can help to assess the intentions of the parties and a clear path to resolution. It all depends on the intentions of the parties and their willingness to correct whatever is not right about the transaction.  A good mediator can point the way forward in that discussion.