Shaolin,

I think that the magnesium shaver style fire-starters are really intended for extreme circumstances in a very wet situation. In those conditions it could potentially be a lifesaver. Other than that possible use, your warnings about the ferocity of the magnesium combustion is spot on. Magnesium is a component in solid rocket motors and in powder form is considered to be extremely dangerous. I know, I’ve used it. So don’t use powdered magnesium for a fire starter. Use Fatwood!