"I can't imagine, say, Microsoft just shoving a GPL library into Office and then trying to argue it in court. That's a massive hint that they know they'd lose in seconds."
If some ex-Microsoft employee (and it would be an ex-employee) put GPL licensed code into Office, and a version of Microsoft containing that code were published, then Microsoft would have the choice of publishing the Office source code, or to pay whatever fine they are given for copyright infringement. Of course they would go to court and argue to keep that fine as low as possible, but they would be ordered to pay.
Biting the hand that feeds IT
