Having everyone take their shoes off to go through “security” is only slightly less stupid than the war on moisture. So on my last plane trip I tried again to refuse. I watched everyone else meekly obeying and I thought: this is personally demeaning and an utter waste of my time and I’m not going to do it. But when I came to the metal detector a woman in a uniform insisted. “Sir, you have to take your shoes off.”

I feigned astonishment. “I do?”

“Yes, sir.”

Meekly obeying, I put my shoes in a little plastic tray on the conveyor belt. “I don’t understand,” I said. “Why do I have to take my shoes off?”

She beckoned me through the magic portal. “For security,” she said.

I continued to act to puzzled. “I have to take my shoes off… for security?”

“Yes, sir, to make sure you don’t have a bomb or something in there.”

“In my shoes?

“Yes, in your shoes,” she said. Her tone had become contentious. “Don’t you remember? — there was a guy that did that.”

“No, I don’t remember,” I growled. My shoes appeared out of the machine. They had been vindicated.

I do remember, of course. One guy did try it. One guy. And he failed: he was arrested before he could do anything. “But he could have done it! He was in the middle of trying to light the fuse!” He did not succeed, and you don’t know that anyone ever could. After all, no one ever has.

And even if you are certain that the trick “could have” worked (whatever that means), that’s not good enough. Even had he succeeded, it would not thereby have become obvious that every traveler on every commercial airline flight should have to remove their shoes. Don’t we need to ask whether the costs exceed the benefits?

The costs are not trivial. Think about two million people every day taking off their shoes, waiting for them to be analyzed, and putting them back on. Everyone suffers a delay, and that costs everyone money. Everyone risks forgetting their other stuff, or having it stolen, while they’re dealing with their shoes. Many will have bought special shoes to reduce the likelihood of being harassed. And everyone risks the extra delay and the extra mortification of being singled out for a false alarm.

And of course there’s the monetary cost of all those inspectors, and guards, and equipment, and space, and so on.

“But we have to protect ourselves against terrorism!” At any cost? Well, even if you don’t think the money is important, remember: the object of terrorism is terror. Now, which scenario embodies more terror: inspecting everyone’s shoes, or leaving them the hell alone?