I think it depends on the connection you use. If I turn off one of my monitors connected via DisplayPort, Windows 10 immediately moves everything to the monitors that are still on. My last computer, with monitors connected via DVI did not do this.
Sometimes I can't get to them at all on the laptop screen without forcing it closed and reopening.
The regular [win] + [left/right] for snapping to 1/2 screen positions will also move it across screens if you hit it repeatedly.
[0]: https://superuser.com/questions/630555/turning-displayport-m...
Sadly MS figured we all wanted to have to shit move around as soon as you use a KVM.
(Also, there's usually a 90% chance that windows will not correctly handle the monitor reconnecting without having to either power cycle the monitor or using the video card's 'really truly scan for monitor changes' feature.)