“Assume that a legislator with courage, influence, intellect, vision, and perseverance manages to enact a law that goes into universal effect and employment on September 10, 2001; it imposes the continuously locked bulletproof doors in every cockpit (at high costs to the struggling airlines)-just in case terrorists decide to use planes to attack the World Trade Center in New York City. I know this is lunacy, but it is just a thought experiment... The legislation is not a popular measure among the airline personnel, as it complicates their lives. But it would certainly have prevented 9/11.
The person who imposed locks on cockpit doors gets no statues in public squares, not so much as a quick mention of his contribution in his obituary. "Joe Smith, who helped avoid the disaster of 9/11, died of complications of liver disease." Seeing how superfluous his measure was, and how it squandered resources, the public, with great help from airline pilots, might well boot him out of office.”
-Quote from Taleb