Re: Technically speaking...
"this is no longer the case as of Windows Vista (IIRC; might be Win7)."
I think it's Vista too. It had to be done so that Windows could offer a Trusted Computing Platform. Not one that could be trusted by end users and IT departments, but one that could be trusted by the "content industry" to provide an end to end tamper-proof copy-protected platform for the delivery of "high value rich media content".