Extortion can be defined as special kind of trade offer that one party (Alice) would prefer to avoid, but once the offer is made, it is in Alice interest to accept it. For instance, Bob asks Alice to pay him money in order to prevent him from damaging her property. If Alice values her property more than the amount of money Bob demands, then it is in her interest to pay him.

It can be speculated that a decision theory that allows acausal trade could in principle also allow acausal extortion: Alice could predict at time t0 that if she doesn't perform a costly action, at some future time t1 Bob will inflict her a punishment that is more costly than that action, even after discounting. Alice could make this prediction even if Bob hasn't threatened her yet.

What is your opinion on acausal extortion?

a) The acausal trade scenario is theoretically incorrect, thus acausal extortion is also theoretically impossible.

b) Acausal trade is theoretically possible, but not pratically feasible, thus the same holds for acausal extortion.

c) Acausal trade is theoretically possible, but there are logical reasons that make acausal extortion impossible even in theory.

d) Acausal trade is practically feasible. Acausal extortion is theoretically possible, but there are practical reasons that make it unfeasible.

e) Acausal extortion is practically feasible and it is or will become a serious concern.