True. For the longest time, I was only able to whistle through my through my teeth and not through my lips. I finally learned to whistle through my lips once I got braces and my teeth straightened out when I was ~14 or 15. Now I can whistle through my lips forwards and backwards, as well as through my teeth.
In fact, I whistle pretty much all the time, especially when I am walking. Sometimes this is accompanied with snapping my fingers, or drumming on my legs or whatever I might be holding at the moment.
The person below me was/is a boy/girl scout.