It's a toned down version of what Israel does at their airports. I've been through it a few times and watched others get the intense questioning. Basically, p

It's a toned down version of what Israel does at their airports. I've been through it a few times and watched others get the intense questioning. Basically, people can confidently lie, but it's almost impossible to keep a story straight when ask about it multiple times from different directions by different people. During intensive questioning at the Ben Gurion airport, you'll get asked about your future travel plans, your past travel history, your family history, their employment and minute details that are hard to prepare for. Then after 20 minutes, they'll start all over again and ask you similar (not the exact same questions) and throw in a few curveballs with incorrect facts - you tell them you're flying to London to visit your aunt who lives in a house in Chelsea, then 10 minutes later they'll ask "So you said you're flying to London to visit your niece who lives in Chelsea, correct?". A normal person would say "no, like I said, I'm visiting my aunt, I don't have a niece", but someone lying likely would just say "yeah, that's correct". And basically you won't get on the plane until they are satisfied with the answers. It's very good at sussing out people out because it's too hard to keep that detailed of a story straight under hours of questioning.