They've done that before, with China. They even explained why they don't just outsource their servers: they don't like risking other people failing to achieve the standards they have set for their service, because that kind of stuff affects Blizzard's image and credibility, not the third-party who messed things up. So even if they were up for it, before you can set up your own World of Warcraft server, you'd have to conform to their standards. Full uptime, as few bugs as possible, integration with Battle.net (that would be tricky), a proper full-time GM staff, all that stuff. None of the private server crews got that yet.