I call BS on their calling BS. It happened to me - with a virtual machine no less. I had a Win-7 machine for testing and left it running (I usually shut them down after using them to save system resources).
I came back on Monday morning and found a Win-10 machine waiting for me. I can’t get it to activate but I kept it for other tests.
Quite a few people it seems are experiencing Sudden-Win10-Upgrade experiences. Is microsoft really attempting to claim that they are all suffering from the same delusion? Then why do so many report identical experiences?