The paintball gun crusader…
Ann Johansson for The New York Times
I had no idea that this happens with paintball guns:
By Michael Parrisha/NYT 14-year-old player inadvertently detached a valve, launching his gun’s carbon-dioxide-filled cylinder as an unguided missile. It struck Ms. Contois, who was watching from a picnic area off the field, in the back of the head. She never regained consciousness, and died at the scene. full article
Apparently this also happened to a 15-year-old boy here in Washington...
The NYT article linked above details the husband of the woman who was killed's crusade to improve the guns.
I know a lot of you paintball. I guess this serves as a warning more than anything else...