Whatever Happened to Common Sense?

 
Steve Mirsky, writing in Scientific American, tells a story that we can all relate to [The Unkempt Results of Post-9/11 Airport Security Rules].

Lewis Carroll’s Alice would have had trouble distinguishing reality from Wonderland had she been with me on the Sunday after Thanksgiving as I watched a TSA officer confiscate my father’s aftershave at the airport in Burlington, Vt. It was a 3.25-ounce bottle, clearly in violation of the currently permissible three-ounce limit for liquids. Also clear was the bottle, which was obviously only about a quarter full. So even the members of some isolated human populations that have never developed sophisticated systems for counting could have determined that the total amount of liquid in the vessel was far less than the arbitrarily standardized three ounces. But the TSA guy took the aftershave, citing his responsibility to go by the volume listed on the label. (By the way, the three-ounce rule is expected to be phased out late in 2009. Why not tomorrow? Because of the 300-day-rules-change rule, which I just made up.)

Feeling curiouser, I did a gedankenexperiment: What if the bottle had been completely empty—would he have taken it then? No, I decided. When empty, the bottle becomes just some plastic in a rather mundane topological configuration. Not to mention that if you really banned everything with the potential to hold more than three ounces of liquid, you couldn’t let me have my shoes back. You also couldn’t allow me to bring my hands onboard. I kept these thoughts to myself, of course, because I wanted to fly home, not spend the rest of the day locked in a security office explaining what a gedankenexperiment was.

I first commented on what I used to call “the illusion of security” in this space in July 2003, after attending a conference on freedom and privacy. We heard the story of an airline pilot who had his nail clippers snatched away by the TSA just before boarding his plane. He then walked into a cockpit equipped with an ax.

Let's think a little more about the gedankenexperiment. If the bottle is really empty then you probably would have discarded it so the empty bottle isn't a good test. What if it only has a drop of aftershave in it? That will be barely visible to the airport security guys but it might give you one more day of smelling nice.

Would they confiscate that? Would they have to open the bottle to see if there was a drop of aftershave in it? What if the drop evaporated during the inspection? Then the bottle would be empty and you wouldn't want to keep it but the security guys won't confiscate an empty bottle. Can you make them confiscate the bottle if they empty it?

What if the bottle has about 2 ounces of aftershave and you pour it into your hands? You now have an empty bottle—which they won't confiscate—and no container with liquid in it, unless they count your hands. What will they do now?

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