Though Apple does have this written in, It probably won't be long before you see Microsoft do this too. Perhaps bonding Longhorns registration with the DRM. so that way you have to buy multiple copies of Longhorn or the family pack. and I know it's called VISTA, but I like longhorn better.
Apple may still back down, but I doubt it. Apple needs the hardware sales for it to survive.
BTW, I figure I'll end up call my new Mac Something other than Macintel. Most likely it will become the Mac + whatever chip intel uses. like Mac MX or something. It's what we do with the G4 and G5 Right?
Macintosh: Intel Inside! Now Improved With Delicious DRM