FUD? No. Exaggerated? Yes.
The layering of OpenGL ontop of D3D will be implemented in Microsoft's OpenGL library, which is not used when you install NVIDIA or API drivers. In fact, this is true on Linux too, Linux comes with MesaGL, an unaccelerated GL which is used until NVIDIA's or ATI's installers replace the libgl.so[.1] links with links to their own GL libs.
Because of this, we may even see Nvidia or ATI find a better solution instead of layering D3D to achieve the same effects. They've been known to actively react to stuff like this.
In the meantime though, I am all secure--I'll probably never run Windows Vista on my boxen.