If there were no adults present, it was either :
a.) Not a BSA function, because all trips by the BSA must have two adult leaders at all times, with a tour permit to allow them to be at said location. So just because they are Scouts does not mean it was a Scout function.
or b.) It was a Scout authorized function, but was negligent on the scout leaders part for not being at their authorized function as stated.
So either it is just a bunch of kids who just happen to be scouts or the negligence of the adult leaders.
If it was the kids.....tough luck on that one trying to hold a minor responsible.
If it was the adults who left them, it is their negligence, not BSA.
Either way, it is not BSA's fault.....