I think lots of people on this thread are missing the point. This won't necessarily detect a determined spy who's done their homework. It's not meant to. It's a

I think lots of people on this thread are missing the point. This won't necessarily detect a determined spy who's done their homework. It's not meant to. It's a quick and effective sanity check to make sure that a person hasn't fudged their visa credentials and they're well in their rights to ask and exercise their discretion. They've been doing it for years. I doubt a perfect answer to their trivia question is required. If it's in your field you'll be able to say something halfway intelligent in response, if you've lied on your visa it will become obvious pretty quickly. Outrage about confiscating phones and demanding passwords is justified. This, on the other hand, seems pretty reasonable.