We need some sort of ransom mechanic. It could be like the war surrender window except when both sides agree on the ransom demands the ransomed ship has to select a destination to warp to. The ransomed ship will then be untargetable by the ransomer until it warps.
A pirate can force a target (player) to pay 'protection' money using a extortion contract. For this option to be available, the pirate must successfully scram & web the target. The target gets 15 seconds to agree paying it.
If the ransom is payed then the target can't be targeted by anybody for 30 seconds (to prevent abuse). Pirate can't be in same corp or alliance as target.