if you opt in, there could be a limited number of places you could be... the target has to be in one of them. The quick travel and the fleet pass could be disabled in those places for both the hunter and the target. There could be a start time for the hunter, and a 2 minute head start for the hunted. If those places are the cantinas in the entire galaxy, you would find each other ... there also could be a ... say two hour time limit for the contract. If one of the players logs off, the contract is nullified. If one of the parties logs off while the other party is near, he loses the battle.