Because there are things called "layovers" and "smoking designated areas."
This latest move is just another piece of nanny-state insanity that will buy us no additional security at all.
No additional security? Okay, so maybe a terrorist isn't going to use a Zippo to hijack a plane. But, I'm more in fear of the prospect of some mentally-deranged jerk taking his lighter and a stack of the nearest airplane magazines and starting a fire on the plane. This isn't nanny-statism, this is just common sense!