And most especially overtemperature, though I recently read that all
   modern CPUs will shut themselves down if they get too hot.


indeed.  time has shown that my laptop needs a yearly fan clean or it
will overheat and turn itself off at 90C, as documented.  the bios will
then complain at reboot, again as documented.  and 'envstat -r' even
seems to report temps leading upto 90C, giving me fairly high trust in
those numbers in the normal running case :-)