My problem with this is that we have little proof that people are any good at this sort of task (i.e. monitoring something without intervening for really long s

My problem with this is that we have little proof that people are any good at this sort of task (i.e. monitoring something without intervening for really long stretches of time). So if data show that people keep failing at it we have to take a look and decide that it's not a good system, not that the people are at fault.