I like it.

well i don't want a 100000000000000000 bounty because I have to kill all those bus turrets...

This is just an idea that I've been thinking about for ages and it's main purpose is to protect newbie's. Here's the basic's of it :

1) Make bounties permanent (not reset after death).
2) Destroying non-defence bots doesn't increase your bounty.
3) Increase bounty by 250(?) with each player/defence bot you destroy.
4) Remove player kills from the ranking page.
5) Bounty decreases by 500(?) per week (2 weeks?).

The idea is that a newb (who's not gonna kill a lot of players) would have a really low bounty and wouldn't make a worth while target AND at the same time it would make newb killers a more desireable target to vets because they'd have huge bounties.

It's just a rough idea and would need tweaking but it does offer the possibillity of proper bounty hunters.

Sounds cool to me

As long as you don't kill the bus turrets too often the weekly reduction should take care of that. Aside from that, we should be able to pay to reduce our bounties faster. Sort of like bribing government officials. It could be a feature that is only accessible in certain, seedier parts of the galaxy.

well let's see... you kill 4 turrets... it takes 2 WEEKS to get back down to 0.
I think it should be more "time undocked" rather than actually just "days" or "weeks" or "time online"

Kills done on a mission for the military or a bounty-hunting mission should not affect your bounty. That way, All nations can have a permanent bounty-hunter mission active for all it's members: "Kill all enemy turrets on sight." The list of enemy turrets can be consistently updated in the mission profile.

That would improve things.

In the future, it may also be logical to have nation specific bounties. So if you make a point of killing Sercos, the Serco nation puts a much higher bounty on you than the Itani or Neutral countries do. They may not even increase your bounty within their borders. I can see specific people becoming "enemies of the state" for different nations. Have "Wanted" billboards of them in certain sectors or put the ones with outstanding bounties up on a list of missions for Bounty Hunters. Besides, once the game gets bigger I doubt the turret brigade will be a significant force. I see it as just a diversion until bored vets find something to do with all their money. Planning long-term changes to the game based on a gang of bus fighters just seems a bit unreasonable.

The weekly reduction was just a quick idea I thought of last night because people who are peaceful sometimes have to defend the flag but don't want a high bounty (And I wouldn't want to discourage flag defending) but there are other possibilities as you've said :

Paying for it to be reduced in 18.
Have it reduce for every hour you're undocked but don't kill.
Maybe even reduce it when you kill other high bounty targets.