There is one female purple belt in Western Canada that hits them EVERY tournament. First time I competed against her I had been warned so I was ultra paranoid. She didn't get one on me, but WHAM! Next guy up, flying armbar.
Some people can just pull those things off.
On the other end of the spectrum I knew a boy who thought he knew how to do them and really hurt training partner when he tried it on her during an open mat time.