The idea that a helmet would not have saved Mike Coolbaugh's life is:
a)
Not necessarily true. The coroner declined to say whether a helmet would have saved his life, and a
Sports Illustrated article states "a preliminary autopsy released two days later found that the ball hit Coolbaugh about half an inch below and behind his left ear." A helmet with earflaps may well have saved his life.
b)
Largely irrelevant. Coolbaugh's death shows that a full-grown adult, with substantial baseball experience, good vision, and good reflexes can be hit by a batted ball. If it is OK to require high school players to wear a helmet while coaching, why isn't it just as OK to require a adult coach to wear one? It seems to me that coaches only took notice of the requirement when they became inconvenienced.
Look. Batters get hit by pitches all the time, and usually a batting helmet does nothing, because the ball doesn't hit the helmet. These days, nobody would argue that batters should be allowed to not wear helmets with the rationale that most impacts miss the batter's head. The rationale that a helmet won't protect a coach against most batted balls, and therefore helmets shouldn't be required just doesn't stand up.
So why should we allow players to be on the field without helmets? Maybe we shouldn't, but there is an obvious reason why it is less important. Contrary to base coaches and bench players, a fielder's sole responsibility at the moment a ball is batted is to track the ball and provide a defense play if the ball is hit to him.
Posters here are probably right, though: Eventually all field personnel will likely be required to wear head protection.