Here's another thought I have about this whole thing. MS constantly says that what it wants to do with this is to stop casual piracy, not the dedicated pirates. I think this last effort pretty is their last ditch attempt to stop casual piracy, because to crack this one, you have to commit a deliberate action. Just re-installing Windows with a different key doesn't work anymore. Therefore, anyone still having a pirate copy of Windows XP after a few months of rolling out this patch is an active pirate and can be prosecuted without arousing sympathy. MS's way of getting out of the way the record labels got blackballed by the internet community maybe?
Cheers,
cgkanchi