> Can anyone here who owned a legit copy of Windows actually say that this happened to them, or to someone they knew?
I can almost say. I had a genuine Windows 7 license in 2011 that I used for gaming. When I'd turn on the machine, it'd give the scary "this copy may not be legitimate" message at boot. When I'd enter the product key, it wouldn't work. I could push through that message, but every 10 or so minutes I'd get a pop-up screen I couldn't ignore that said "this copy may not be legitimate" and I'd have to enter my key that should work that doesn't, or hit "ignore for 10 minutes."
So, Microsoft didn't remotely deactivate it, but they, through their error, inconvenienced me such that I got rid of something that was a $300 value (it was Win7 ultimate, 32 and 64 bit licenses. I got it for free by hosting a Windows 7 launch party. So it's the most genuine Windows you can get.)
I'm a case study of "DRM provides no advantage for legitimate users, and occasionally inconveniences them." Of course I'm just an anecdote, but you asked!