I have never been asked to reboot dannyboy, that is up to the user as far as I know.
It happens with a number of Distros, Mate, but only occasionally. Not sure with KDE, but know of no reason why same would not apply. We had this debate over 12 months ago with friend bmike1 I think. Only then did he notice it, coincidentally with an update that followed.
When I install a new Distro (typically once a week), if the .iso is a few months old, there may be a hundred or more updates to be run, and I always reboot to be sure that changes take, and that no conflicts are generated with my other Distros.
And if you ever run
sudo apt-get dist-upgrade
to install packages that have been held back, it will often regenerate GRUB, and I likewise reboot if I am not prompted. Kernel updates likewise.