I think it is a rather clever idea. It is a reasonable metal for light-weight medium strength applications which is why it is used in engine blocks in lawn-mowers and VWs. It would have a clever dual use. Shavings could be cut from it to light a fire in a pinch. (Why not one stake be made of a magnesium rod and one made of ferrocerium?) As for flammability, I did a little test to confirm what I learned in school. I heated a small block of magnesium in a campfire until it was too hot to touch. I could not ignite it. Shavings and thin ribbons, on the other hand, ignite easily.
- Tikki
P.S. If you go to market, send me a prototype