When we read about Lufthansa’s recent move to allow passengers to self-board airplanes at its Frankfurt hub, it gave us pause. Was this, we asked ourselves, a brilliant step in human self-determination or a recipe for certain disaster? Lufthansa’s Quick Boarding system lets passengers scan their own electronic tickets at the gate and then walk through subway-esque turnstiles to board the aircraft. The airline estimates that the system cuts boarding time by 25 percent. Perhaps the Germans can get this right, but my pessimism about the human condition makes me wary about a system like this - and not for any security reasons. I’m imagining some college kid trying to scan his own retina with the machine and octogenarians piling up like sandbags at the customer service desk nearby. What do you think?