I've actually switched to Software602 for my own personal use because of this problem. Apparently I did this just in time. Now I'll have to consider Linux for the same reason. Much of the low-level family bootlegging that goes on is actually accidental. If a machine fails completely, for example, the operating system may have to be installed again.
People grab whatever disk they can find when they do a reinstallation.
Families usually have only one well-organized member, and the disk tends to be taken from that person. With Windows XP, this kind of installation will fail eventually, when the computer checks in with master control in Redmond. Now I understand why Microsoft officials think this is a good idea. It's not worth it. So Microsoft is going to force the issue.