- The scanner isn’t judging you for being sweaty; it’s just too dumb to know what sweat is.
Are you one of those people who always seem to get pulled out of the airport security line for a pat-down even though you made perfectly sure to empty your pockets? Have you wondered why that is?
Well, not to be rude, but it could be because things are a bit swampy down south.
A lot of things can set off an airport security scanner and flag a false alarm. However, overwhelmingly, one of the most common causes is water, such as sweat sitting on your skin.
That’s because the Transportation Security Administration’s (TSA) body scanners aren’t simply metal detectors. They see a lot of things, but sometimes they think they see stuff that’s simply not there.
Such as your drenched groin.
But why does this happen, and is there anything you can do about it? Let’s take a look at why TSA’s scanners want to take a look at your sweaty crotch.
The Scanner Can’t See You Naked — Anymore
First, let’s dispel one common concern among privacy-minded travelers. The TSA body scanner isn’t alerting the authorities about your scrotal sweat because it can see your private parts.
These machines don’t see you naked. At least, not anymore.
Unfortunately, we’ll have to tell you that there was once a time when these scanners showed the security agent what’s essentially an image of your naked body. These early machines had no privacy (or decency) protections, and allowed the security staff to see you in your natural, if somewhat blurry, glory.
That said, to try and make it so that nobody could associate a naked body with a face, the agent viewing the scan screen wasn’t usually at the security gate. Instead, they sat in a separate room and radioed their colleagues about any possible issues.
These types of body scanners, however, were removed from all airports by 2013, according to the TSA. As such, you won’t have to worry about anyone at the airport seeing you naked.
Blind as a Bat
But if the scanner doesn’t see your body, what does it see? Very little, actually.
Modern TSA body scanners are, in technical terms, called millimeter wave scanners. They use a process called Advanced Imaging Technology (AIT) to take a peek at what you have on your person.
The tech works a little bit like a bat’s echolocation. When activated, the scanner sends out a blip of millimeter waves, or ultra-high-frequency radio waves.
Although these waves penetrate through your clothes, they’re perfectly harmless to your body. When they hit a solid enough surface, they bounce back, and the scanner catches the returning waves.
It then compares the return signal to the average “skin response” programmed into its memory. If the scanner determines that a certain spot doesn’t seem like skin, it alerts the security staff.
Even then, nobody can see your naked body anymore. Instead, the scanner places a marker on a gingerbread man-like avatar for every suspicious response it gets.
Then, the TSA agents go to work to give you a thorough pat-down.
Suspicious of Everything
Now that you know how the body scanners work, we can finally get to the big question — why does it get suspicious about a sweaty groin? Well, we kind of answered that already.
As we said, the machine compares the return signal to what it believes human skin should send back. However, the range of what the scanner considers “human skin” is very limited.
That is partially by design, as the TSA doesn’t want to make it easy for people to sneak dangerous or illegal objects on planes. However, it also means that any number of things can confuse the scanner.
It will certainly pick up the watch on your wrist or the car keys in your pocket that you forgot to place in the tray. But it also reacts with suspicion to things like bra underwires, piercings, or jewelry.
Even layered clothing or a particularly large mole on your body could trigger an alarm. Yet, by far, the scanner’s worst enemy is water.
Passing through water, such as sweat sitting on your skin after rushing to the security check at the last minute, seriously disrupts the radio waves the scanner spits out. Consequently, the signal that returns to the machine might look more like a handgun than sweaty underwear or armpits.
Unavoidable Issue
So, let’s say you’re a frequent traveler who suffers from scrotal sweatiness. Is there anything you can do to prevent the scanners from picking up your problem?
Sadly, not really. You could try wearing some moisture-wicking underwear, but your best bet is to arrive at the airport with plenty of spare time so you can stroll through the security check at your leisure and avoid sweating.
You can also decline to walk through the scanner — that is within your rights. However, if your goal is to avoid a pat-down, that’ll be a counterproductive solution, since it’ll earn you just a more thorough groping.