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Hey there!

I am the subject of the article and to my knowledge I wasn't 'assessed' in any formal capacity (certainly not at the level of cross-referencing anything with Wikipedia)

I am thoroughly convinced that just getting down and putting code on paper in a confident way got me across that border!

So, if I had any advice for others it would be to do what you normally do in a software interview: act really convincing - even if you're a bit flustered!

I think it's common, and that's part of the tactic, to see if you're lying. Not based on your answer, but based on your reaction.

In 2004, I wanted to drive to Canada with a friend. She was from out of town and hadn't brought her passport. I wanted to go anyway, so I just left my passport at home as well and drove up there anyway. (I remember the pre-9/11 days and figured, no big deal, even though they CLAIM you can't get back into the US without one).

The border agent coming back into the US asked us each a rapidfire series of questions meant to throw you off.

"Where were you born? How long did you live there? What's the major industry in that town?" All quickly, before you even really had a chance to finish your answer.

After asking us each a few questions he just smiled and thanked us and waved us through.

> One cannot but wonder what happens if you answer the question in a different manner than that suggested by Wikipedia or whichever resource the CBP draws their questions from.

They're looking at your overall attitude, not checking your knowledge of trivia. Answering the question about inverting a binary tree wrongly still means you understand what "binary tree" is and can at least come up with a couple of sentences with that term that sound coherent and resemble what is written in Wikipedia in broadest terms. For comparison, ask your non-engineering friends to answer the same question, even to try to fake an answer as best as they can.

I strongly suspect that they actually look at how you react and behave when presented with the problem rather than what the solution actually is.

I know it's popular to view border guards as complete dolts interfering with everyone's day, but they certainly deserve a bit more credit for what they do.

> I think the basic idea - questioning people about things they ought to know, given who they claim to be - is a good one.

It's an awful idea. False negatives. Discriminates against people with harder professions. Wouldn't keep out determined people

As to the last part, if people are sufficiently determined, you're in for a hard time, anyway. A 30-second screening at the border is pretty good at sorting out the Epsilon minus semi-morons, though. (Whose numbers, one would suspect, vastly outdoes the really determined ones.)

As for false negatives, I wouldn't be too concerned as long as you got to talk to someone reasonably well versed in your field. Also, as suggested by golergka and rconti - they probably use the questions as a way to elicit a response from you and judge that, more than your actual answers. That makes a lot of sense to me, now that I pause to think of it for a second.