JimL, your post #27 has that piece of information which has caused some measure of debate. I've got the scars to show for it!!!!
I know context is everything, but its little wonder people may have erroneous beliefs.
Although minor surface damage to a gear or bearing is unlikely to be instantly catastrophic, and should be detectable, and although gearboxes are tested to run for a period such as 30 minutes with the oil supply failed, the possibility of a major failure within the box is ever present.