“I was just asked to balance a Binary Search Tree by JFK's airport immigration”
I think there&#x27;s been quite a bit of overreaction here.<p>Part of their job is simply to determine that you are who you say you are. They do this every day - within reason I expect they can ask you any arbitrary question related to you and your life to observe how you respond. They just want to catch those out that aren&#x27;t, for whatever reason, being genuine about their story.  I think there&#x27;s a false assumption here that somehow @cyberomin&#x27;s ability to actually _solve_ a BST was in some way tied to his likelihood of entry. That&#x27;s obviously ridiculous. I imagine his response was still genuine enough that they believed him. Frankly as another commenter joked, I think they could have asked him to prove P=NP. It&#x27;s when you reply confidently with an &#x27;obvious&#x27; solution that they might raise an eyebrow.<p>Yes it would be unreasonable if their ignorance actually lead to you being denied entry. But in not one of the experiences here, or with @cyberomin, was that actually the case. The thing is, of course, that they&#x27;re aware of their ignorance and the absurdity of their questions. You see, they know that they&#x27;re bluffing. That&#x27;s kind of the point.<p>It is, perhaps rather unfortunately, part of their job to make you feel uncomfortable, ask probing questions and weed out inconsistencies in your responses. Isn&#x27;t that part of professional questioning? I can understand the frustration at the abruptness of the questioning, and it&#x27;s hardly a friendly welcome. I&#x27;ve been angered leaving immigration before and I have to remind myself that ruffling my feathers is all part of the act. When first complaining to a friend she asked, &quot;what did they insult you or something?&quot; Actually, no. They just asked me lots of questions.<p>Clearly I&#x27;d like to think some questions are off-limits - I know there have been justified concerns about this - especially recently.  And I understand this is hot topic right now - precisely why I think we should be careful - more careful than ever - not to overreact.  From what I observe: The guy arrived, he was asked questions about his profession, his answers were evidently sufficient and he was let in. It happens to thousands of people every day. Honestly? I don&#x27;t think there&#x27;s a story here.