AF - I take the point you are making but at 400 hours a year that's what part time airline pilots do. And given proper initial and recurrent training I can see no reason why a private pilot doing 400 hours a year will have standards that are any less than an airline pilot. And like private pilots, professional pilots also screw up. But well managed ones with proper operating practices screw up less. When they do get it wrong, they also accept input from the person sitting next to them to prevent a minor error getting out of control. And this is where the one man band is found lacking. If he gets it wrong, he finds out the hard way because there is nobody else to point out his misdemeanours. And this could be after a long day at work. Flying two crew on any aircraft is more than twice as safe as flying single crew, as proven by hull loss numbers in any year you would like to mention.
PM