Meh, dig your own grave Microsoft. Slowly but surely, you'll get deep enough for the mounds of dirt to collapse on their own weight and bury you.

Unless what they're afraid of is that license being used to try to force opening of Microsoft's code because the Windows Phone 7 is being distributed with the open software, if you, say, give the phone to someone else while FOSS is installed - but is that even a valid understanding of how GPLv3 works? Because as far as I know, it can only apply to things that are 'distributed with' the software under the same licence, not just distributed with arbitrarily.

Meh, I just don't see them at all benefiting from this in the long term.