Yes, I was required to wear a 'chute when I flew jumpers. This was based upon the risk of either being flung out of the plane in the case of an upset (which had happened many years earlier), or the risk of a jumper damaging the plane so it was unflyable, and had to be abandoned. The jumpers used to tell me that they would reach to touch the horizontal stab (C 185) on the way out, and could not touch it. I took their word, having no interest myself in attempting this. I can imagine the reasoning could be different for a Caravan, as the pilot being flung out is very unlikely - no open door nearby, and I thing an errant jumper incapacitating a Caravan is even less likely. As I think about it, unless the pilot's door of the Caravan were to be modified so as to be jettisonable, I can't imagine the pilot getting out without an immense and unlikely cabin transit effort.
This does not explain why the child was aboard, but it sounds unlikely that a 'chute would have helped either of them anyway...