clearly beneficial action of giving money to the mugger.

If someone threatened to blow up the world with their magic powers unless I gave them a dollar, I'd say a better guess at the right thing to do would not be to pay them, but rather to kill them outright as quickly as possible. In the unlikely event that the mugger actually has such powers, I've just saved the world from an evil wizard with a very poor grasp of economics; otherwise, it's a valuable how-not-to story for the remaining con-artists and/or crazy people.