>It then becomes valuable for the original owner to secretly mine a chain, attempting a 51% attack. Depends on how able the injured party is to retaliate. In

>It then becomes valuable for the original owner to secretly mine a chain, attempting a 51% attack. Depends on how able the injured party is to retaliate. In ordinary life, bouncing a check often results in actual or threatened legal action. Disputes between criminal organizations are sometimes settled extrajudicially. So I would not expect the sender to attempt a double-spend if the recipient has the capacity to respond either legally or illegally.