Maybe, according to a report by the Windows Secrets newsletter that found nine files in Vista and XP that were being updated by Microsoft without the system owners' permission.

The issue is whether Microsoft is overriding some users' decision to decide when and if updates are installed. Microsoft prefers it when users opt for automatic updates, but users give up some control of their system when they go that route.

From the report:

"It's surprising that these files can be changed without the user's knowledge. The Automatic Updates dialog box in the Control Panel can be set to prevent updates from being installed automatically. However, with Microsoft's latest stealth move, updates to the WU executables seem to be installed regardless of the settings -- without notifying users."

But there's a twist. Nate Clinton, Windows Update manager, said in a blog post that what's happening is that the update software is automatically updating itself.

That's a little different than Microsoft sneaking system updates on your PC without permission. Clinton said Microsoft is, but Clinton acknowledged that Microsoft could have been more transparent about how this works:

The point of this explanation is not to suggest that we were as transparent as we could have been; to the contrary, people have told us that we should have been clearer on how Windows Update behaves when it updates itself. This is helpful and important feedback, and we are now looking at the best way to clarify WU's behavior to customers so that they can more clearly understand how WU works. At the same time, however, we wanted to explain the rationale for the product's behavior so our customers know what the service is doing: WU updates itself to make sure it continues to work properly. We are also confident that the choice to use Automatic Updating continues to be the right choice.

So at the least, Windows Secrets provided a good service highlighting the situation and pressuring Microsoft to better explain updates.