Their operating system costs as much as the computer nowadays. I'm sure they're going to have to raise the bar in anti-piracy schemes in order to (try to) keep the piracy rate of Windows Vista down.
However, it seems as if they have not really thought this through. Either that, or they must be pretty damned sure that they've squashed all of the bugs in their piracy detection algorithm.
What if another situation happens like the world-wide beta test of Windows Genuine Advantage that went out as a critical update? Entire corporate keys getting blacklisted would prove to be quite harmful to the Internet and world commerce, especially if it happened to a big company. All of a sudden all their virus/spyware/firewall protection shuts off, and voila, they're all wearing red capes at a bullfighting arena.