Ah. My comment assumed its parent comment was written by an American. My point was that, if you hailed from an country with a common culture, it would be trivia

Ah. My comment assumed its parent comment was written by an American. My point was that, if you hailed from an country with a common culture, it would be trivial not pick folks out of a crowd who share your cultural background. I don't think that Americans would not have such an easy time doing this.