My point wasn't so much that it will cause a black hole, as that a tiny amount of disutility times 3^^^3 is going to be unimaginably horrible, regardless of how small 3^^^3.

Is the problem that we are failing to evaluate what happens if everybody else makes the same decision?

That's not the problem at all. Thinking about that is a good sanity check.If it's good to make that decision once it's better to make it 10^30 times. However, it's only a sanity check. Everybody isn't going to make the same decision as you, so there's no reason to assume they will.