Episode Summary
Executive Summary: PJ Vogt investigates why several men are repeatedly flagged by TSA body scanners for crotch/anus anomalies. After comparing listener reports, internet theories, and expert explanations, the team tests the hypothesis that sweaty or wet underwear triggers false positives. Their experiments suggest moisture is the cause for these cases, though follow-up tests show the issue is not fully universal and the mystery remains partly unresolved.
Main Topics: Listener-submitted airport security mystery: The episode begins with three unrelated listeners describing the same strange TSA experience: body scanners repeatedly flagging their groin area, leading to pat-downs in public. Internet theories about large anatomy and false positives: PJ surveys online discussions and media coverage suggesting that large genitals, scar tissue, or body geometry can trigger TSA alarms, but these explanations do not fit the listeners’ claims of average anatomy. How TSA millimeter-wave scanners work: An engineer, Doug McMaken, explains that millimeter-wave scanners use radio waves to detect anomalies and replaced human image review with algorithmic flags after privacy backlash. Engineering causes of scanner anomalies: Doug outlines possible causes like corner traps, clothing deformation, and moisture, connecting the machinery’s design to how bodies and fabrics interact with radar waves. Field experiment on sweat/moisture: The hosts wet PJ’s underwear and later have Garrett recreate a sweat-level condition; both are flagged, supporting the theory that moisture can create false positives. Replication, limits, and unresolved edge cases: When Travis later tests the dry-crotch method, he still gets flagged on repeated passes, and Keller also fails the dry test, showing the explanation is likely incomplete or not universally applicable.
Key Arguments: The recurring TSA flags are unlikely to be caused by sexuality or by unusually large genitals, because all three listeners described themselves as anatomically average and one described himself as straight. Millimeter-wave body scanners can misread moisture because water changes how radio waves bounce, creating apparent anomalies in the crotch area. The machine’s false positives may be a modern artifact of the TSA’s tradeoff between privacy and automation: replacing human screeners with algorithms reduced privacy but introduced ambiguous box-flagging errors. Internet folk explanations for TSA groin flags are widespread but unreliable; engineering explanations are more plausible, though not always definitive. The episode’s experiments provide evidence that wet or sweaty underwear can trigger alerts, but replication failures show the phenomenon is broader and not fully solved.
Data Points: Listener questions received by Search Engine in a year: 4,589 - PJ notes the volume of audience questions reviewed during the year. First listener mention of the issue: 2017 - Travis found the earliest text account of being flagged in his message history. Second listener’s email date: July 12 - Silas’s email about the TSA groin anomaly arrived after Travis’s interview. Third listener email date: August 31 - Keller’s message made him the third person in two months to report the same issue. TSA body scanner privacy rule change: 2012 law / 2013 TSA compliance - Congress required changes, and TSA replaced human image viewing with algorithmic flagging. Underwear bomber attack date: 2009 - Abdul Muttalib’s failed attack drove interest in body scanners and underwear screening. Incognito Mode discount: 20% off for six months - Promotional offer mentioned at the start and end of the episode. NYU applications deadline: January 6 - Career advice and program promotion for the NYU Podcasting and Audio Reportage Program. Current year reference in transcript: December 2025 - The episode notes the mystery remains unsolved as of that date.
Pivotal Quotes: "What do the TSA agents see when I go through the body scanner?" — Silas: The email that first alerted PJ to the second listener with the same problem. "The body scanner scans you, compared to what's expected, then reports any anomaly." — Anonymous Redditor on r/tsa: An online explanation of why larger-than-average anatomy might trigger the scanner. "Bro, what is this?" — TSA agent: The agent’s reaction when PJ entered security with deliberately wet underwear during the experiment.
Implications: The episode suggests some TSA groin flags may be caused by moisture interacting with millimeter-wave scanners, but the problem is not fully solved. Travelers may reduce false alarms by staying dry; the TSA’s algorithmic screening still has opaque edge cases.