From the InformationWeek post:
Windows Update does not automatically update itself if automatic updates are turned off, according to Microsoft’s Clinton. However, Windows Secrets reports that it found the updates downloaded and installed even under those circumstances. Even Microsoft’s own reports appear to be inconsistent: Windows program manager Nick White writes on his blog that “self-updating is done regardless of whether the user has enabled automatic checking, download and/or installation of updates.”
I can verify that these updates are installed automatically, and silently, if you have automatic updates enabled.
Aside from the obvious ethical implications here, this is a potentially heart-stopping nightmare of a back door.