How does airport security search through one's luggage?

Varies widely.
Here are a few variants, based on my experience:

They touch. I don’t. I wish they’d let me:

Leaving USA to UK 2003. Checked bags. Customs came out to us and asked for keys and vanished again. They took the top off a LARGE container of dairy whitener using not the proper clip on lid but a secondary filling-only seal. This did not close properly after inspection and the whitener escaped top contaminate everything in the bag. Alas, in the final rush it was put in the “technical bag with electronic gear and was deliquescent. We ended up cleaning wet sticky goo out of everything all round the world. It would have been nice if they HAD involved us.

They “panic”. ‘No blasters!’ I touch. Just as well. We all breathe a sigh of relief.

Southern Ireland (Dublin). 2003. Incoming from England. Carry on bag XRayed at customs. Lady customs officer approaches me with nag. places it on bench in front of me and steps back. I sense she seems tense and look up. She is on balls of her feet and there is a semicircle of customs people at some distance behind her. Summat aglae. “Would you please open your bag for me sir?” I CAREFULLY and SLOWLY open bag and on request and slowly remove contents. When I pull out the small collapsible tripod with fold out knife blade legs and screw extending 3rd foot plus and G clamp mount (a handy tripod that I’d bought in Venice) and place it on the benchtop, I feel the tension relax in a wave, the half circle of customs people saunter off as if nothing had happened and the lady relaxes. Well, OK, I guess it COULD look like a handgun od an XRay. Or maybe the blades looked like knives. Or … .

Same trip many weeks later. Sydney Australia incoming from Thailand. “Would you please open your bag for me sir”. Oops. OK. This time I knew what the issue was :-).

They take me to a back room. They touch it all. I touch it all. We have a party (OK, not quite) .

Qingdao, China. Olympic City during Summer Olympics. (I didn’t get to see any). Wait for LARGE checked bag packed with vast array of parts and a full electronics workshop, more or less. (Going to a factory where test equipment was not certain to be available and I wanted to be sure to be able to do resting and to prototype design changes on the spot.) Wait for bag – Wait for bag – Wait for bag … . Finally. Last on carousel. Oh well. It did not occur to me that this was significant. Walk up to customs. Quite a few questions. Then, would you come this way please sir. Take me to a side room. About 6 customs officers present. THEY unpack ALL my bags. Then they hand me various items and ask me to explain them.
“This is a packaged unopened set of O-rings, made in China, sold in NZ, bought back to China by me.”
“These are resistors/transistors/ICs/ ….”I had many CDs with me. Some commercial program disks. Some recorded with technical material by me. Quite a few blank.
“We will take your CDs away and read them.” OK.
And so on for almost every non clothing item.
No problems. I was far more amused than concerned. This may have not been wise BUT I knew I was squeaky clean and that they would find nothing (genuinely) untoward. After what seemed a long time they allowed me to repack and leave.

Class B drugs. I declare them. Nobody touches.

Entering Australia from ?Beijing?. 2008?
Customs officer. “You’ve ticked ‘drugs …’ here”.
Me. “Yes. I have some Class B drugs – prescription medicine.
CO “How much and why?”
Me “Probably about 20 to 30 tablets. Prescribed for my own use.
CO “Have a nice day”.

They XRay. They ask. I explain. Nobody touches. // We touch, they help.

In Belgium I bought a “drinking horn” for my son – a medieval reenactmentist.

Incoming AK NZ from Thailand. NZ is VERY strict on agricultural imports – we are very isolated by oceans from major disease sources and want to maintain our condition. (eg Only major landmass with NO Rabies)
All incoming baggage is XRayed with equipment designed to give a colour indication as to whether contents items are biological or inorganic.
Agricultural officer: “Have you got a cows horn in there?”
Me “Yes. But it’s plastic”:.
A.O.” “Ah. I wondered why it was green”
🙂
ie the equipment identified and outlined the cow horn shape BUT also showed that it was inorganic.
Without this we would all have been doing some handling.

On another occasion incoming to NZ we had a “hikers” tent that had been used in country areas in Australia. We had ensured that it was dirt free but they wished to check. We unpacked it from our bags and together we checked that it was indeed dirt free.

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Detecting “biological” items:

The terms “Organic” & “Inorganic” essentially mean carbon chain related or not. In the text above I mixed my terms. Better maybe would be to say “of biological origin, or not”. I’m not certain how they differentiate but probably use XRays in the “water window”.
Wikipedia: The water window consists of the soft x-rays between the K-absorption edge of oxygen at a wavelength of 2.34 nm and the K-absorption edge of carbon at 4.4 nm (x-ray energies of 530 and 280 eV, respectively). Water is transparent to these x-rays while nitrogen and other elements found in biological specimens are absorbing. These wavelengths could be used in an x-ray microscope for viewing living specimens.

Commercial suppliers:

Smiths detection

Nuctech

Wikipedia – Cargo Scanning

Muon “scanning” !!!!

Compass full body scanners – wow / agh / ugh

FDA Q&A

When I went to Japan I was asked on arrival in Tokyo to open different compartments of my bag for the security guy to look through it, but it did not get scanned.

Before departing from Sendai airport after a scan I was asked to search for an item in my bag based on the description they gave me(Turned out to be a bottle opener which wasn’t allowed as it had a knife).

In several countries in Europe, and in Africa often objects for identification in the hand lugagge were handled requesting me to produce them until a decade ago. Lately, I flied to spain and they handled it alone.

As for the luggage, in Europe never been asked to deal with it, once in USA and routinely in Mozambique it was often inspected in my presence.

It depends on what they think they will find. And on the local laws and protocols. Those differ greatly from country to country.

When a security officer opens a piece of luggage they can have an idea of that is in there if they scanned it before hand. But even that does not show dirty underwear or other substances you don’t want on your hands. So they wear gloves. People don’t like it if their luggage is handled by strangers. So unpack out of sight or let the owner do so.

Easy: And that means that if they don’t think you can do harm to yourself or others, protocols will make sense to let the owner unpack. This is not a fast thing, so for speed they will do it them selfs.

Danger: if for some reason the security personel don’t trust you. (doesn’t have to be a reason you care for or understand, try to travel to Israel for some fun on this part) they will not let you do a thing. And in all times will want to have control over the situation, you and your luggage. And so you will not touch a thing.

tdlr: depends on a mix of the following:

• (Perceived) Danger level
• Needed speed of search
• Rules against theft (paper trail of opening)

This depends on the airport. In the US, they search it whenever they want and place a notice letting you know that they did so, with a reference number for the case. I have gotten this notice close to a hundred times as I normally have a tripod in my checked luggage and that suitcase always gets the notice.

In Central and South America, they call passengers to come down to the luggage area. They first issue a generic announcement such as Would passengers John Smith and Jane Doe report to the service counter. Then they escort you into the secure area where luggage is screened and asked the passengers to open it. This happened to me in Guatemala City, Panama City and Quito at least. On most occasions they search the bag themselves in front of you and help you pack it back. In Quito, they also make you sign a form acknowledging the search. Other times they do not touch the bag and you are asked to produce objects from it that match a specific shape shown on the x-ray.

In Europe, Asia and Africa, I never got called not gotten a notice but I did see a fellow passenger being asked to open his own suitcase in Africa. My guess is that they need to have the passengers there at least when they do not have standardized locks like the TSA’s. Otherwise, they would have to break them, which is possible in some places.

When I, and a number of other passengers, went down into the bowels of Guayaquil airport to have our checked-in baggage searched we were asked to identify out bag. The staff member then searched the contents himself and then, much to my surprise, helpfully repacked it for me. It was mostly used clothing from the trip so it did not need meticulous folding. Given the number of other passengers involved I think these were random checks and they had not been alerted to anything by screening.

Anecdotally: The one time I’ve had the security screener take an interest in my bag — at Berlin-Tegel about a year ago — he showed me a suspect contour in the x-ray image and asked me to pick the item out of the bag so he could see what it was. The bag was then scanned again without it.

(The suspect item turned out to be a drawing compass that the screener thought looked like a butterfly knife mechanism in the x-ray image).

I suspect it will go differently if they decide I’m suspect and they need to do a full bag search.

In my experience, the traveler is not allowed to touch the luggage or its contents during the search. This experience mostly comprises searches by the US TSA, with a few in Germany and probably the Netherlands that I do not remember very clearly. I imagine that other countries might have other protocols that require the traveler to participate more actively in the search.