Windows Media Center is
infected with “Macrovision.” Macrovision is the crippleware that some
TV stations and networks use to stop you from recording their shows.
Though there is no law requiring manufacturers to install this kind of
Macrovision — and though it's not illegal to ignore Macrovision and
record a show anyway — Microsoft implements it for WMC, and infected
its customers with it after disguising it as an “update.”
Microsoft probably did this to bribe the cable
operators into giving it access to encrypted television, though it's
possible (and legal) to record their shows without permission by using
the analog outputs (like theNeuros OSD and mythtv, a DIY Linux-based recorder).