Simple advice, yes. I would disagree on the 'easy to follow' part - it's very difficult to stand your ground against someone with the authority and powers of a police officer, especially in a tense or confusing situation. Alternatively, perhaps the officer is presenting things as a completely innocuous situation, where only someone like a sociopathic, unhelpful criminal with something to hide would refuse to respond, and so on. It makes it very psychologically demanding and emotionally draining to keep saying 'no comment' and yet still remember that you are doing the right thing and absolutely have the right to keep doing so.
