Many thanks to the discussion of cages and explanation of theories hypothesized and tried. It helps us all as we try to do the best thing to protect ourselves and our families. It has already made some changes to a revision I've been planning for my cage.
It's very human to project ourselves into this awful accident, and guess at causes or actions that may have prevented it as a self defense while the reality is our hearts all break for these folks, and at what could happen to any of us.
Three things I know to be true:
1. Life is a vapor
2. Focus daily, and put your energy into, only those things that matter
3. Don't wait