Well-documented, maybe, but not consistent. I just changed the processor on one of my computers (from a single- to dual-core AMD), and I didn't have to re-install or re-activate.

Anyway, I hope OP does have luck suing them. Supposedly Windows Vista will be even worse -- it is only allowed to be transferred to a new computer once, and Microsoft wont' even say what 'new' means, so it could just be a small hardware change. After that, you have to buy a new copy, whether or not you provide them with your personal information.

btw, ScottC, The OP can correct me if I'm wrong, but I think the issue is not that re-activation is necessary, but that they try to trick you into buying another copy instead of re-activating, then if you persist they demand your personal information when you attempt to re-activate. Those two items probably aren't in the license agreement!