by enabling the view of protected systme files in explorer, you can see even the supper hidden file and folders. The only place that I have seen this not be the case is in temporary internet folders, but I think I could be wrong.
You might try putting a $foldernam$ in %systemroot% and see what that does. Those are reservered for service packs, but I suspect that you can hide them if you want. Now the Sony DRM that is out, you can use that, but you put your self at risk by letting it run.
hope that helps some.