Joy's laptop just got Windows 10.
It didn't bother asking. It announced it. "Windows 10 in 14 minutes 30 seconds!"
Then, after the reboot: Do you agree to the license? You have to say yes. Do you want Cortana? You have to say yes.
No option for "Bugger all this! Put my computer back the way I had it!"
At least my Windows lab machine hasn't done that. Yet. I made the registry changes to disable the GWX nonsense, and Microsoft hasn't overridden them. So far.
And it looks like the important-but-out-of-date software Joy is using wasn't broken by the change. Again: so far. Given that Windows 10 doesn't have a stable API, who knows what'll break next week?
If I wanted that experience, I'd be running Sid.