Well I was asked a similar question but not in the US, and I can tell you that it can catch you off guard given the right circumstances, even if you aren't guil

Well I was asked a similar question but not in the US, and I can tell you that it can catch you off guard given the right circumstances, even if you aren't guilty. Are these guys trained enough to tell the difference? The way I see it, it's not going to make the guilty people stumble, but it will lead to false positives. In the long run, I think asking such a question does more harm than good.