From the article:
Free markets aren't perfect, because they merely reflect the imperfect actions of human beings. Free markets can't create utopia, or a world free of risk and violence. But airport and transportation security can be vastly improved, with a better bottom line: more people making it home safely. When we offer an alternative to grossly incompetent and sclerotic state bureaucracies in providing security to high-crime areas, conditions improve. And that's the real goal of libertarian "ideology": a better world, not a perfect one.
Very interesting read about applying free market ideas to security.