I had a cloth sheath for my old opinel that kept on opening, so I made myself one to make sure I won't lose (more) knives! Made from a single piece of 9 oz leather (plus one for the belt strap on the back), it won't ever let my knife fall out! It would probably be strong enough for LARP use, and since it's not too modern it'd work pretty well I think.

Maybe I'll do some for my other knives, who knows? I could even make one for preople who'd like one!