It also requires some ideological bubble where people care too much what other people know and think. Otherwise someone would never bother that kind of an educational talk with a stranger.

I played kind of the same thing a little while ago. I and a friend wanted to watch a movie, "Blast of Silence" it was called. We met in the bar two people, one of them I knew, the other one asked what we were about to watch, I answered "Blast of Silence", pronouncing it completely wrong (our mother tongue is some sort of German), she thought I made a joke and I told her with a completely straight face that I didn't learn English in school as I was going to a very basic school. I had to completely rely on the subtitles. She was a little bit embarrassed to have brought it up. moral of the story: you have to play dumb convincingly then you can have a little bit of fun