Accidents do happen, even if we try to claim that they never should. I will accept that these men were "doing their best." Heartfelt sympathies to all. I would hate losing any of my fellow Cub Scout leaders and I would punch anyone of spoke ill of them.
My heart goes out to these men and their families. We can all learn from what they did, but it will take quite a few man hours to piece together all the facts of this case. I would hope the men were aware of their situation, but odd things do happen. The big Aggie bonfire tragedy comes to mind.