That's how I understand it. All I was saying was, state that the diamond is to be split, and whoever refuses and bows out first gets to keep the entire thing, as they would have demonstrated genuine concern for its welfare.

The scenario is obviously not the same - that's the joke. (Which apparently did not land.) The critical difference is: It's better to get part of the diamond than nothing at all. Thus, when any party is presented with the option to take part of it, their only sensible action is to take it. Either it's going to be split anyway, and no one would want to give away their share to the other scoundrels, or all parties are going to come together and refuse to allow it to be split - which leaves us back at the beginning.

The same cannot be said for babies. Who wants part of a baby? Not me