Recent reports suggest that terrorists can now create bombs so thin that they cannot be detected by the current X-ray screening that our carry-on bags undergo.

In an effort to protect against such threats, the United States is considering banning laptops and other large electronic devices in the passenger cabins of airplanes flying between Europe and the United States. This would extend a ban already in place on flights from eight Middle Eastern countries.

Given the significant disruption such a policy would cause tens of thousands of passengers a day, a logical question any economist might ask is: Is it worth it?

It is tempting to think that any level of cost and inconvenience is sensible if it reduces the risk of an attack even a little. But risks, inherent in flying and even driving, can never be avoided entirely.

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