My understanding is that US airports are generally not configured to separate transit passengers from the rest of the airport (there is a term of art for this but it is eluding me at the moment). As a consequence, if you're in America even for a few minutes, you'll meet with our good friends at Customs and Border Patrol. CBP is not TSA.

Right.

When I was living in South America I met hundreds of backpackers from all over the world that were forced to go through the US on their way South. Many of them had hilarious, stupid and scary stories of how customs treated them when they only had a ~2 hour layover and had no interest in the US what-so-ever. They all vowed to never fly through the US again, even though it will result in higher flight costs.

The term that I've heard used for this is sterile transit. I'm not aware of any US airports having it.

LAX has it, I've been through on the London to Auckland route, both ways.

Both times they didn't have enough staff to man the separate customs desk, and ran us through a general customs hall.

It's been and gone a few times over the years on that route. At times immigration but no baggage claim, at times transit lounge (actually I'm not sure I ever did go through when that was in force, I think it came and went in-between trips for me), at times full re-check-in... anyway, I think the setup was different every time. And every time they found a way to make it a PITA. I eventually got fed up with it, and don't travel that way any more.

I prefer via Dubai, Hong Kong, or Shanghai. Border control officers there, while still clearly doing their job meticulously, manage to be polite as well.

There are a few other airports that do, too, but it's uncommonly used.

Interesting, as far as I seem to remember all the airports in Europe I've been to had this concept, except tiny regional airports. Probably because traditionally pretty much any connecting flight involved transit through a third country that you'd need a separate visa to visit.

The idea is that you "enter the country" when going out from the main part of the airport, but you can go from any arriving flight to any departing flight without doing so, and most of the facilities - shops, waiting rooms, etc - are 'inside the zone' as well.

Customs require you to reclaim any checked bags too, so you can be sure of meeting TSA before you get on another flight.

Last time I passed through LA on the way to NZ from London, and back, I was eyeball scanned and fingerprinted. I had a moan about this here:

https://news.ycombinator.com/item?id=6566274

At the time they didn't appear to be siphoning off folks for hand-luggage special treatment, though it wouldn't surprise me if they did.

"Bio" scanning. Reminds me of a trip out via London Luton a year or so ago. They were "trialling" one of those hugely expensive and ineffective backscatter scanners. We, my partner and I were pulled out of the flow and asked if we'd like to try it. "We can't decline, can we?" I ask. "Ha, ha. No. But it is really safe." The operator when into sales pitch mode. I said I was well aware of the technology but understood it to overall reduce security because of the money wasted that would otherwise be spent on trained personnel. He repeated again that it was safe, by which point my girlfriend was already shepparded into the device. "I mean," he jokes, "you're not pregnant are you?" "Yes," she honestly replied, now standing arms raised in front of the sensor. After a short pause, another assurance of safety followed. I said I would happily undergo a manual search, but he said that would not be required. Scan over, we were let go. "Well," my partner began as we strolled passed the duty free, unable to really pay attention to it now. "That was humiliating." Indeed it was.

The answer is yes. All travelers arriving on international flights are screened by CBP, regardless of whether they are transit passengers. Before you go through CBP, you must collect your checked bags, which means after CBP, you must be dumped into the insecure area of the airport, rather than the sterile area. From there, you will need to clear TSA security to make your connection.

TSA searches only usually apply at the transition points from the outside into the terminals. Not all airports have the terminals all connected on the "secure" side though, so if changing airlines you may have to go through them.

Customs is a different story, and I'm not sure how that works in this case.

When connecting from Country A to Country C via Country B (i.e., flight goes from A to B, then another flight from B to C), some countries offer "transit" -- they do not require clearing Country B's customs or security, and simply allow you to step off one plane and onto the other.

The US is not one of those countries. When connecting between two other countries via the US, a passenger must clear US Customs, then US TSA security procedures before being permitted to board the second flight.

I've transited through the US at LAX before, and while I did have to go through customs, I did not have to go through TSA.

Would be good to compare that risk with the risk of passing borders in countries prone to corruption. How could we compute stats about that?

From my experience crossing the Syrian border many many times, it's resolved with (at most) a 20$ bill(or the equivalent in Syrian pounds).

Same goes for traffic violations or pretty much anything that deals with the police or customs in any way.

I'm guessing that this wouldn't be the case for someone whose name is on a list somewhere or someone actually caught smuggling something(might work but would definitely set you back more). But at least in my(and friends') experience, it's never been a problem specifically because of the corruption. Police and customs people are not robots following orders from on high, they're robots who'll bother you to no end until you pay them and will leave you alone and might invite you over to a cup of coffee once you do.

When I lived in Kenya, I was stopped for speeding. In a battered old Peugeot 305 estate. Up a steep hill on a main route. At 8000 feet altitude where the already underpowered engine was suffering greatly from lack of air. The policeman was looking for a bribe, but got laughed at instead.