The way I see it, the not losing bounty against yourself is a check against one person controlling the pirates for an entire game. I.e. you might be able to send the pirates in 1,2 or 3 or more times against a person (assuming 1v1) but after a while if you haven't lost anything, the bounty against you would be so high as to be prohibitive, and you would have to face up to a pirate attack.
Personally I would love to see the pirate code re-written anyways. The way it stand right now, pirates are the most un-pirate like group imaginable. Pirates exist as a group that seeks maximum profit for minimum risk. As it's written now, the pirates in the game are ALWAYS suicidal. Therefore none of the pirates in a given raid ever survive to spend any of the profits earned, so why would a pirate risk his neck to raid in the first place?
I imagine a pirate code where the pirates when they raid would pick the least defended system (based on sometimes bad intel) of a given player (still influenced by bounty), jump into a system with a vasari like phase gate system (or maybe an unstable worm hole type thing that players could see if they were paying close enough attention) and run in to destroy support structures and steal resources from the planet. If successful after a few mins in grav well then they would beat a hasty retreat out with their stolen loot. If the player managed to intercept them before this they could get the stolen resources back.
Something a little more realistic like this would make them more interesting, would cause players to invest a little more in defense for non front-line systems. Would still make later game pirate raids have more meaning than just xp farming for low level cap ships too.