After reading a few of the online reports regarding the accident at Mokuleia, a few thoughts.
Unlike the remainder of the group, the victim had not yet put her helmet on as they approached the crag, or possibly had removed it. The group was still walking along the approach trail at the time of the accident.
The rock's size estimate and distance of travel vary from one report to another. A 25 lb rock fell 20 ft., or a 30 lb rock fell >50 ft.
Such a rock fall impact would have far exceeded the design parameters of most rock climbing helmets.
The camp group was lead by counselors and did not have the proper permit.
There is a local commercial guide service that works that crag, but there is no record of them having ever had the appropriate permits either. Apparently, ranger inforcement of the permit policy has been weak.
As for closing the park to climbing, maybe it's a knee jerk reaction, but rock climbing is a relatively new activity in Hawaii, and isn't considered in the park's master plan.
Now as the result of a tragic accident, they're forced to review the activity and hopefully for the local climbing community, make positive and appropriate adjustments to their master plan.
Best wishes to the 12 year old victim, for a full recovery and hopes that this event doesn't prompt the permanent closure of the state's most popular climbing venue.