In my experience it's been true. I actually use it to my advantage when I'm at work (I barback at a busy restaurant so I constantly have to let people know when I'm behind them to avoid and collisions and spills). At first it was a huge problem not getting the words out in time, but I found if I just say "behind you" in a slightly melodic way, not singing but not speaking flatly, it works much better and I haven't gotten stuck yet doing so