Woke up one morning to a very hot Thinkpad in my bag. Windows 10 did exactly that. Extremely frustrating.

I have never had a Windows laptop boot up for scheduled updates. In that event, it always waitied for the next manual boot.

Yeah, I haven't either, that's why I said "I'd love to see you try". You'd think the system would be smart enough to realize that it's literally never been awake at 3:30am.

The ACPI power spec allows the computer to set an alarm and have it woken up at a particular time... like 3:30am

I experience that constantly on any laptop I use because I pretty much never turn them off - they go to sleep mode when not used. Every now and then I find the laptop running with a clean desktop after logging in - because it decided to reboot and install updates somewhen during the night.

I've been an enemy of automated updates ever since, many years ago, I went to the kitchen to boil the water for a tea, and there suddenly I heard the PC speaker beeping - oh, Windows decided to count down from "5 minutes" and reboot.

I think automated updates are fine but require user's intervention to restart. Don't restart automatically on their behalf.

They are not fine. For example, Outlook (on my work PC) tends to become non-functional when an update is pending.

That's just P* poor quality and lack of care at Microsoft. When I think of automatic updates, I am thinking about automatic security updates on Ubuntu server. I'm sure canonical will screw things up at some point as well though.

I guess it is easy and tempting to say "just turn it off and on again" on consumer electronics and end user computers. :/

Why would an application become non-functional when an update is pending? Perhaps a critical security vulnerability?

If the computer is sleeping it can wake up. Not sure about hibernate.

It can't in hibernate because it's the state as shutdown. The deep sleep introduced in new versions of Windows might still be able to wakeup though.