How is it that, when you pass through the airport security gates, sometimes they beep and sometimes they don’t regardless of your apparant lack of objects that would set them off??
This is really bugging me…
They do this to confuse the would-be terrorists. A terrorist, sneaking a nuclear bomb onto a plane, hears the beep sound (at random) and gets all nervous and starts sweating and looking furtively around… and the alert security guards detect this anomalous behaviour and seize him. Or her.
Really? I just had it down to some kind of inconsitency in the sensors…
Are you being serious about the beeps going off just to antagonize would-be terrorists? I was on military orders to CO about three weeks ago, and was practically strip searched at the security gate. I have a security clearance from the military. The freakin’ military trusts me, but these jackoffs at the airport don’t??
First, I was asked to remove my belt–when I was not wearing one. I had taken all of my change out of my pockets and put in my carry-on (specifically to NOT set off the alarms). When they found out was not wearing a belt, they said it was the rivets in my jeans. I wasn’t really strip searched, but I had to remove all outer clothing except my shirt and pants, and some woman felt me up–just in case I had a bomb between my legs or my breasts. I was really embarrassed because this happened out in the open. There was no private room or anything.
I know that these people can’t exempt certain people from these searches, or else the terrorists will forge the necessary paperwork to impersonate someone from that group of people. But, the question you posed in the OP, green_dragon, is really interesting. That the beeps go off randomly–or at least not for a real reason. The other person I was travelling with said that she was stopped once because her “boots had the same density as C-4” Which I DO NOT BUY. (I’m sure everyone already knows this, but C-4 is an explosive.) 4 semesters of chemistry have taught me that x-rays have nothing to do with density, just a two-dimensional picture of the items in her bag. Electrons excited, chemical signatures, yes, but density??
I’ve also heard that people with the military leather boots get stopped because the boots have a metal shank that runs under the heel to the toe. This sounds much more reasonable to me than the C-4 density one.
I’m sorry to hijack your thread, but I’d like to see someone start a thread about “Ask the Airport Security Person.” Any of you out there? From my experience and some others above, it seems that reasons are made up on the spot to detain people. Is there a statistical thing that you follow? Is there anyone that can answer questions about this without giving up tactical information?
The thing they scan people with is a metal detector. Only luggage is x-rayed (unless you meant that, not that she was wearing them).
I don’t buy the ‘going off at random’ theory. Airport security is slow, tedious, and inefficient enough without adding some totally random element to the mix!
I think the answer to the OP is that its just a limitation of the technology and experience of the people using it. The detectors need to be calibrated & adjusted periodically, so some are just more reliable than others.
And obviously, post-9/11, the policy is to err on the side of caution.
4 years of chemistry apparently didn’t teach you a thing. While density is a function of many properties, not all of which are related to X-ray shadow, the density of most solids does correlate fairly well with impermeability to X-rays. While not strictly accurate, “density” is a perfectly reasonable (and common) shorthand for “property of blocking X-rays.” Since this property is exactly correlated to the darkness (er, or lightness) of the shadow in the X-ray, it’s exactly what they should have said. Nonetheless, I’ll translate: “the boots produced exactly the same darkness of image on my fluoroscope that I’d expect from a similarly sized block of C-4 plastic explosive.” 'K
Maybe you should have studied physics?
Also FYI:
Military boots? Most high-quality shoes have a steel shank, and most people wearing them have to take them off. I wear sneakers at the airport.
No, the military does NOT trust you. Your security clearance is the result of the exact opposite of trust – the military has checked you out far more thoroughly than any airport security guard ever did. They just had the luxury of doing most of it behind your back, and they didn’t do it while you were waiting for a plane.
And, finally, everyone, of course the metal scanners are inconsistent. The sensitivity is determined by the airport, the security personnel, the manfacturer, the technician, and the various non-human factors that affect electronic equipment. Yeah, I’m pretty sure Dex was putting you on. He does that.
My 2 pennies:
I took a flight last week. I passed through security once with no problem. A half hour later, I left the terminal to go down to check-in to look for a traveling companion that was late. The second time through security I went through a different metal detector, right next to the first one, and this time I set it off. I was then subjected to being pulled aside, told to remove all items from pockets, shoes, and belt and then “wanded” with the hand-held detector thoroughly. As he was sliding the wand between my legs and over my crotch, I asked the guard why I didn’t set the detector off the first time and he gave a curt “dunno”.
I can surmise three possibilities:
- The second detector was set to be more sensitive than the first.
- My passing through security twice was suspicious enough to warrant a closer look at me.
- Security randomly pulls people out for closer screening and it was my lucky day.
#1 is the most likely, as the detector did beep. However, does the operator have the ability to make the detector to beep at will, as a way of alerting the other security personnel to those that fall under possibility #2 or 3?
Well, I’m fairly sure this is true, except it had nothing to do with the metal detector in my case. I passed through without a beep, and they said, “You have been selected for a random security screening. Please step aside.” They certainly didn’t make any secrets about it. For one flight, I was checked three times (baggage check, security checkpoint, and boarding gate) and each time they told me it was a random screening. I think that was probably pretty exceptional, though. 
It seems to me that some people’s tinfoil helmets are getting a little loose.
I travel a lot both before 9/11 and post.
I have had metal detectors go off on my second or third leg in a particular days flying. (same clothes, no coin, keys, or cell phone) I have always chalked it up to very slightly different detection thresholds of different units.
Since 9/11 I have taken to wearing boots with no metal shanks, a Velcro belt, and I empty all my pockets before I get to the machine. I haven’t been stopped for secondary screening since.
To get terrorists nervous from the beeps doesn’t require any extra input from the security screeners. There are enough idiots in line carrying enough metal to have the damn beeps going off all the time. It makes me want to post a pit thread about how despite it misleading name a metal detector detects metal. 
Oh and if they want to go over you for a closer screening all they have to do is ask you if you would mind submitting to a voluntary screening.
No, I was not being serious. Sheeeeesh.
Dexter, my tinfoil comment was not aimed at you.
I’m just waiting for the time when a terrorist gets caught hiding explosives in an orifice south of the navel.
Can you imagine the stop checks! :eek: