[Jtsummers]

It's a tradeoff. Trusting computers too much gets you into trouble (loss of navigation skills, over reliance on a potentially faulty system), but having to do things manually and depending on discipline also doesn't scale. You need to maintain enough discipline (validate the computer's results) but still have a better source than "Well, myself and three others looked at this chart for an hour and couldn't find anything above 350FT".

Discipline works until time pressure causes discipline to relax, and then the loosened discipline becomes the norm (normalization of deviance). There is no reliable way to restore discipline (in a timely fashion) after that happens, and then a collision would become inevitable. If you only rely on discipline, you're bound to fail. If you have means of relieving the reliance on discipline and don't use them, you're making a tragic mistake.