How would this be any different to a business based on selling unauthorised printer cartridges/refills? (Serious, not rhetorical, question!)

(All under the assumption that making unauthorised use of the Kinect does not require copying a work that Microsoft owns the copyright to, of course).

I don't think it is different. What's sleazy about printer cartridges isn't the lock-in, it's the teaser price on the printer made up for with the artificially inflated price of the cartridge.

Sure, but are those printer cartridge businesses in potential legal trouble?

Almost sounds like a deliberate troll, doesn't it?

My comment, or the comment I'm responding to? Preemptively: The fact that what I actually believe flies in the face of the conventional wisdom on Hacker News does not make it a trolling comment.

Microsoft's legal threat.

I think it was dumb of them to pick that fight, but that in the extreme they are invoking, it's not an idle or frivolous threat.