Traveling for the holidays? No need to fear missing your plane because you’ve lost your government issued I.D.! You can fly without it—as long as you know the color of your house.

A few weeks ago I lost my wallet, or maybe it was stolen. But I had to fly from Los Angeles to San Francisco, and I didn’t have a single piece of identification—no passport, driver’s license, credit card, work I.D., nothing.

When I got to LAX, I approached the uniformed Transportation Security Administration agent nearest the entrance to the security screening area. She had the power to ruin my day, and we both knew it. But I was sweet, and she was only slightly superior in return.

I was really happy to get on that plane that day. But I wasn’t thrilled to learn that instant access to satellite images is a government tool of airport identification.

“Do you have anything?” she asked. “A library card? A bill addressed to you at your home?”

I shook my head from side to side, pitifully.

The agent summoned the supervisor. He carried a clipboard and something that looked like a cross between a World War II-era walkie-talkie and a 1990s cellphone.

“Please write your name and address on this form,” he said. “Then I have to make a call. The gentleman I call will ask you a series of questions to help us verify your identify.”

I filled out the form super-neatly, so I wouldn’t seem like a nervous terrorist, and the supervisor placed a call on his phone-a-ma-jig to an intentionally unidentified person who I came to think of as the Voice.

The Voice spoke to me directly. “Have you ever lived in the Washington, D.C., area?” the Voice inquired. “Yes, a number of years ago,” I said. “Do you now live in a gated community?” asked the Voice. My neighborhood isn’t technically gated, but there’s only one road in and out, so I answered, “Yes.” That was the right answer.

The final question from the Voice, the one that got me through the backscatter machine, past the shoe swipe-o-meter and onto the plane, was a stunning surprise: “What color is your house?”

“Green,” I told the Voice, who then asked me to hand the phone back to the supervisor. The supervisor and the Voice then began chatting about how nice my house was.

By chance, when I got back home, I had an email waiting for me from Mr. Peter E. Sand, director of privacy technology at the US Department of Homeland Security in Washington. He was inquiring about a book I’d written. I quickly emailed him back about my experience at LAX. How did they know the color of my house? Why did they ask me that? Sand volunteered to put my questions to someone who might know the answer.

That person turned out to be Peter Pietra, the director of privacy policy and compliance at TSA. This was Pietra’s exact reply: “[Y]ou are not allowed to fly unless you can present acceptable I.D. to match up with your boarding pass. Because we know this can be a problem for people who've lost/forgotten I.D. or may not have acceptable I.D., we developed a process to help passengers who want help by using a variety of ways to try to verify that the person standing at the checkpoint without I.D. is actually the person on the boarding pass. While this typically involves asking questions from commercial databases like Lexis-Nexis or Choicepoint, sometimes they will try to look the address up on Google Earth and see if there are questions they can ask that someone at that address should be able to know. (What is a cross street, is there a park across the street, etc.) To get the house color I assume the house must have a photo on Google Earth or some similar website.”

The idea that an airport official can tell me the color of my house as a favor to me when I lose my wallet is a bit disconcerting. I was really happy to get on that plane that day. But I wasn’t thrilled to learn that instant access to satellite images is a government tool of airport identification. It feels invasive. And does knowing the color of my house really prove that I am me, anyway?

I could almost accept government use of invasive-feeling technologies if such technology were used consistently, by all levels of government, without infringing on civil liberties. But although the government sometimes makes scarily efficient use of technology, it sometimes does the opposite by failing to make use of technology, with terrible consequences for personal freedom.

Here is a case in point. Last month, my nephew’s house was robbed. (He lives in Atlanta and I think his house is yellow.) The thief stole electronic toys, computers, and televisions. My frantic nephew called the police to report the crime. When they arrived, they asked my nephew his name, and of course he told them. They placed him under arrest.

The police claimed my nephew was wanted in Tennessee for drug offenses. My nephew has a fairly common name, and when they heard it, the police arrested him and dragged him to jail, leaving his wife and four children behind in a state of shocked disbelief.

One would have thought that big-city police would have electronic access to arrest records, photographs, fingerprints, and other information. They should be able to clear up a case of mistaken identity speedily. But my nephew sat in the Fulton County jail for two days. It took two whole days for a judge to order him set free.

Get the irony? It took two minutes for TSA to determine to its satisfaction that I was the lady who lived in the green house in Pennsylvania. But it took two days for a big-city police department to determine that a man, a crime victim, found inside his own family home was in fact who he said he was, and not some guy with a similar name from Ohio wanted for selling dope in Tennessee

Proof again that technology is only as good as the people who use it—or refuse to use it.

Anita L. Allen is the Henry R. Silverman professor of law and professor of philosophy at the University of Pennsylvania. She writes about everyday ethics, health, and the right to privacy for scholarly journals and the popular press.