If you aim a little higher it will count as a headshot. However to perform this helmet shot you have to take into consideration the age of the man. As gravity tends to pull a little more length to junior. By the time your in your eighties, you are effectively hung like a tape worm.
Fox News caused a furor with Bulletstorm's crotch shots. Wonder how they will react to actually see a CG "tape worm" being slowly torn apart by a bullet in this game.