Problem is that the humans operating any kind of machine which has some form of "safety watchdog" don't think much about the risks involved in that machine operation because they know other humans (sometimes lot's of them) have previously thought on how to check for a fault or a bad configuration with that installed lifesaving watchdog device. Operators leniently remove themselves from the "fear of unattended failure" state of mind, stepping outside the danger loop, having more time to contemplate other stuff related or not with the machine operation.
If anyone tries to remove all the "danger" sense of any operation (because it's so freakin' safe nowadays), people will tend to leave the machines dangerously to their own devices; when operators spot a problem they usually get in to the loop at a later and stage, unless they keep themselves consciously on alert i.e. using the watchdog device as a confirmation tool for an earlier recognized problem.
GD&L