I'm sorry, this comment is not necessarily a reply to you directly but to the thread in general--are we talking about the real world or some fictional TV show? Genuine question, is this something a "normal" HN reader should be worried about? Is there any evidence of such incidents happening ("kick open your door and bust in with flash bang grenades")?

I see no reason why a robber posing as a cop would want to draw more attention to themselves than necessary.