Airsoft guns? meh, what a bunch of pussies.
I don't see why fights to the death aren't legal. Well, they probably are actually if you do them in the right place, so yeah let's have a real battle royale, that would actually be interesting.
Oh and how can you mention a bunch of movies and stuff in regards to Battle Royales and not mention the movie Battle Royale? It's probably the original, and even if not it's surely the very best. One of the best movies ever full stop!