Have you ever broke one that way? Where would put the lighter that it's directly in contact with bones? Try bash one against the hardest snow you can find, with any part of your body where there's a pocket, thigh, belly, chest, arm, and see if you can break one.

I've smashed lighters, and it takes a hammer or a rock, not something you can do with even your fists. Try it, and see how tough they are.