STANDING in line at security at San Francisco International Airport not long ago, family in tow, I dutifully pulled the laptop out of my bag and placed it in a separate bin for its solo trip through the X-ray machine. I also had an iPad in my backpack, so I caught the eye of a security agent. “Excuse me, does the iPad come out too?” I asked.
“Not here,” she said. “Other airports might be different.”
This was not the moment for a follow-up question, but I was curious: What’s the distinction between the devices? Similar shapes, many similar functions, the tablet is thinner but not by much. Is the iPad a lower security risk? What about the punier laptop-like gadgets, the netbooks and ultrabooks? What about my smartphone?
Safely back at my desk, where a follow-up question wouldn’t risk triggering delays that could spread throughout the nation’s air traffic system, I began investigating what seems like an existential question for the digital age: When is a laptop a laptop?
There must be a reason the laptop is singled out as the bad boy of electronics at the airport. Or has the world of gadgets moved so quickly since 2001 when the laptop rule went into effect — and back when the tablet and smartphone were still in the incubator — that federal regulators have not kept up?
I called Bruce Schneier, the security chief for British Telecom and a long-time security expert with hundreds of thousands of miles of airline travel under his belt (a belt that, he noted with pride, never beeps in security because he’s chosen it carefully). If the laptop question confused me, it had him sounding baffled.
“Is it thicker than an inch, wider than a piece of paper, bluer than the sky? Who cares? It’s all nonsense,” said Mr. Schneier, who is also the author of a new book on the psychology of security, “Liars and Outliers.”
Next stop: T.S.A. They ought to know, right? It’s their rule.
A spokesman said the agency has its reasons for still requiring that traditional laptops go through X-ray machines in a separate bin. But he declined to share them, saying the agency didn’t want to betray any secrets.
As I did more reporting, the logic behind the rule grew as elusive as a free power outlet in the boarding area. Is size the issue? If so, security experts counter, today’s laptops are far thinner than they used to be.
Could it be because laptops, unlike tablet computers, have an easily removable battery compartment and hard drive that could be used to hide homemade bombs? But some netbooks and ultrabooks have similar compartments, and they don’t require separate screening. Strike two.
Perhaps, I thought, it’s because the circuitry of a laptop can be replaced with a device to send an electromagnetic signal to jam an airplane’s controls at takeoff or landing. But, as I soon learned, the same circuitry could be embedded just as easily in phones, watches or game players, all of which stay in the bag.
I was starting to feel like a Monty Python character, riding a pretend horse, clomping my coconut halves together to simulate the sound of horse hooves. A comical quest for a mythical grail.
The T.S.A. wouldn’t comment, obviously, on whether laptops are better carrying cases for bombs. But the agency’s “blogger team” was on the case, having published several posts that acknowledge the potential confusion created by the popularity of so many new gadgets like digital readers and tablets.
“I’ve read many a post from people wondering if these items should be treated like a laptop and removed from their carry-on bags,” reads the first T.S.A. post on the subject, from April 2010, in an explanation signed “Blogger Bob, T.S.A. Blog Team.” Bob then writes: “Great question!”
The post explains that electronic items may stay in the bag if they are smaller than the “standard-sized laptop.” Laptops and larger electronics should come out so that screeners can get a better look at them and see more easily into the rest of the bag. Blogger Bob writes: “It’s that simple.”
Right, like quantum mechanics. About six months later, Bob chimed in again, writing a post in response to questions about the MacBook Air, a new line of slimmer Apple laptops. He reiterated the previous rules but added an extra rule related to screen size, measured in inches.
“With those rules in mind, the 11” model of the MacBook Air is fine to leave in your bag, and the 13” model must be removed prior to X-ray screening.”
So wait. Screen size is the guiding principle? At last, fellow travelers, a lead. I went back to present my smoking gun to security.
Michael McCarthy, a T.S.A. spokesman, would only reiterate the agency’s position about laptops, declining to elaborate. The blog post from November concludes by offering, if not more clarity, then at least good wishes: “Removing laptops or anything resembling a laptop has become part of our security DNA, so we thought it best to send out a refresher to our workforce. Enjoy your gadgets! I know I do … ”
Insert sound of clomping coconuts. This quest wasn’t leading to clear answers, nor particular enjoyment, just more theories.
So I turned to Robert Mann, an airline industry analyst, who, it seemed, might finally put the matter to rest. “I can only assume that it’s the volume of the device,” he began promisingly. “But,” he continued, “some laptops and certainly many netbooks are actually smaller than the so-called tablets. Yet by being a so-called laptop they would probably fall under the security net.” He paused, then added, “It’s a difference without a distinction, at least from a security standpoint.”
BACK to zero. Until I happened upon a security expert who asked that he not be identified because he has worked on related issues with the Department of Homeland Security. He said that the laptop rule is about appearances, giving people a sense that something is being done to protect them. “Security theater,” he called it.
Mystery solved? Quest completed or at least abandoned, coconuts retired. Maybe this wasn’t about security after all; it was about making us think it is about security.
Just when I’d decided it was time to limit my airport questions to asking about the whereabouts of the nearest power outlet, this source added an ominous twist: If the government really wanted to cover the dangers posed by electronics, he said, it would need to carefully inspect all manner of electronics, from phones to netbooks to tablets, to look for increasingly small and sophisticated weapons.
However, he added, “banning every computer-related device on planes would be absurd.”