@neil But it's a much harder technical problem; extracting stats and checking they're a reasonably close match to one known reference (your passport) is fairly easy. But what's the reference in this case? It might work if you can do it against the recently-landed-flights, so it's a comparison against a few hundred people.

@penguin42 @neil see recent https://www.bbc.co.uk/iplayer/episode/m001s8qd/the-secret-genius-of-modern-life-series-2-1-passport by the awesome Hannah Fry. There's literally a demo of how this works by scanning everone as they walk down a hall.