I see it as a futile exercise because since I would have died then I don't get to know who is more intelligent and even get to see the fun part of the quest. Rather, when I am sure I have enough to sustain me in my life time then I can give them the quest in my life time for the rest while I watch them and ensure the rules of the game are kept so they don't get to kill each other and in case no one is able to break it, I can provide them the solution rather than losing the whole coins forever.
(hypothetically) When I die I'd like my children to have all my bitcoins. So I was thinking of writing a will to give each of them equal amount but to make it more fun I'd hide the keys from my wallet and make it a quest.