I'd start sabbing his BPM's. You could do more per sab attempt and then he'll break them once he attacks you if I understand it correctly. Plus they are more expensive than the IS. That way at least he can't get any usefulness out of your money.
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I hit this one guy with no officer for all of his gold.... He retailiated 5x15 turns I sabbed him a few times then hit him again for half the amount I originally got from him. (apparently he was hunting) I got a message from him and someone else in a chain that he joined. I calmly explained my position and included the flame that he had sent. The other guy basically laughed at this dork and now if he attacks me again, I have their permission to slap him around
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