(And what kind of decision theory requires a third party to make precommitments before you can make the right decision, anyway?)

3PDT, perhaps? ;)

And their claim afterwards? Any threat you can make, they can make. You see why this is a dead end?

That's kind of what I'm trying to point out here. It is a dead end, but I'm actually claiming the below. Sure, someone else can also claim the below as well. We can both make the claims. Now, who do you believe more?

But lets formalize my claim. My claim is that I will make n+1 utilitons happen if n is positive or n-1 utilitons happen is n is negative, as long as you do the opposite of what they tell you to do.

Where n is how many utilitons they offer given any result.

I'm outside of your conception of time. So if they make the threat after this is of no concern to me.