There is a chap with the name Ken Barlow on Twitter that is friends with my wife. He is not the real one but is very funny in a typical dry way. https://twitter.com/I_am_KenBarlow
He spent three weeks with one of those gently stretching the story out until they gave in. He then pushed a little further and found out it was a 6'3" Nigerian male who was in a room with 30+ others. He had on average 6 sessions open with different people at the same time and only 1 in 500 ever took the bait.
I remind myself of this person's experience every time a dumb twonk asks me yet another stupid question (for the fourth time).
If you use Twitter and want a laugh it is worth following Ken Barlow. He also comments on various TV program's in a wonderfully sarcastic manner. He was the one that introduced me to the wonderful parody that is "The Tripe Marketing Board" https://twitter.com/TripeUK