SB I think it is possible for the matches in a water proof match case to ignite but the chances of doing this are I think very very small, in the event that they do I think most match cases are going to vent rather than explode which could result in burns but that is obviously not as severe as an explosion. I tried to go back and read your original post but it has been deleted, if I remember right you were in effect building a rocket using depleted CO2 cylinders, this is a totally different situation, I once attended a training class where the instructors demonstrated the use of match heads as a replacement for gunpowder in a metalic cartridge but I don't think I want to try that one. I would not worry about carrying matches in a waterproof case. I think the risk is so small as to be insignificant compared to other risks you face in outdoor travel much less a survival situation. I have never even heard of it happening or found any reference to it, not to say it hasn't but I would think if it had documentation would probably be fairly easy to find.
To kind of put it in perspective, I have been involved in incidents where people have been accidentally shot by others, accidentally shot themselves, fell into the fire and burned themselves, cut them selves severely with a knife, and axe, been injuried by venting camp stoves/lanterns, hit by falling rocks, trees, and limbs, struck by lightning, been attacked/injuried by wild/domestic animals, impaled themselves on all manner of objects, the list goes on and on. Now before you think I am the unluckiest person alive, it is part of my job to deal with the many ways people find to hurt themselves and others in the great outdoors. The point of this is there is a certain amount of risk associated with anything we do and we must weigh the risk verses the benefit and decide for ourselves, I have carried matches in waterproof cases for years over thousands of miles and have never had an incident but they sure have been handy a few times. I think in this case the risk is worth the benefit but you will have to decide for yourself. This might be a good one for the Mythbusters TV show.
