Would you allow your children to participate in such a contest with each other?

My son and daughter (ages 10 & 9) have this weird game they like to play that they picked up from watching an episode of Big Brother. Specifically, they like to re-enact the punishment where two cast mates are handcuffed together for 24 hours. They lock themselves together with a pair of toy metal handcuffs my son owns and they have me hold the key for 24 hrs. The only time I'm "allowed" to unlock them is when one of them has to use the bathroom. I guess it's a bit of a case of monkey see, monkey do. They also say they enjoy the challenge of having to work together in order to be able to play, etc. I was a bit concerned by this game at first, but after seeking the advice of other parents, I had decided to just let them have their fun, figuring they'll get bored with it eventually, that all kids imitate what they see to some degree, etc. Lately, however, I've been having second thoughts. They told me just today that they'd like to see which of them can stay handcuffed the longest. If I allow them to play, it'll be like before. I'll hold the key and unlock them when they need to go. But they don't want to be released after 24 hours. They want to see who can outlast the other, however long that takes. What do you all think? On the one hand, I'm tempted to say that after 24 hours they'll get bored with it and asked to be released anyway. On the other, that's what I thought the first time they ever asked to play this game, that they'd get bored with it after a couple hours. So should I let them do this? Should I be concerned at all about this?