Wore one when I was younger and parents told me to one wear one for baseball. Once I hit high school, I only wore one in baseball when catching. If I was playing OF or pitching, no go. I did wear one for football in high school. For college baseball, if anyone wore one, it was the infielders. But by that level, they know how to protect themselves when there is a bad hop.
Now that I coach high school age players in travel baseball, no one ever wears a cup unless they are catching. The umpire always asks at the plate meetings "are your players properly equipped?". Every coach always says yes and just gets on with it.