I got caught by this; I bought a Microsoft phone (W8.1) which bullied me into creating an MS account for reasons I didn't quite follow, but it seemed harmless.
I had bought an Asus laptop with W10 a month or two before. The next time I tried to log in on it, I found I was locked out until I could find the scrap of paper I had noted the MS password on.
I called Microsoft "helpline" (ha, ha, ha) during this episode, it was some time before I realised that the moronic half-wit I was trying to explain the problem to was indeed a robot, and not just an MS geek who sounded like Stephen Hawking. I had wasted a lot of choice obscenities before I twigged.