I've noticed this too and it's very frustrating.  I did an 8 player 3 star FFA and I noticed that the 4 AI's that didn't share a star with me didn't spend a penny on bounties, while every AI on my star did.  That makes me wonder if the AI's do gang up on the human (or at least don't recognize each other) - surely that other star had some rivalries going on that pirates could have helped with?

You are playing ffa (vs. locked teams), choosing to use pirates, and playing with an unfair setting to boot, and then you are complaining when things are... unfair?

Placing a bounty on one AI usually had this effect - he bountied you back with more money. Now you are one of the two favorites again.

Solution - you have to make MORE favorites for a bounty.

Try bountying three different AIs for 500-750 credits before you have any bounty on yourself. That usually forced them to start placing bounty on each other, at least in all my games I was safe for 2-3 raids after doing that until all the accumulated bounty dispersed.

Try that and tell us how it went.

i've noticed this problem ... try putting bounty on 2 or 3 ai players at once.. seems to fix this for me

I can't speak to unfair AI, but on Easy (I am starting slow on Diplomacy), the AI were more likely to target each other with bounty than me.

Just did a quick game to test out AI bidding under well controlled conditions.

It was me and 5 hard AI (I'm assuming hard doesn't cheat?), LOCKED teams (yes, the AI are all on separate teams) and this was the first pirate raid.

Here's what happenned:

Pirate raid alarm goes off, and by the time I look at the bounty display there's already 250 on my head.  My average ranking is ~3.  No bids on anyone else... time to fix that.

500 on AI 1, 750 on AI 2, 1000 on AI 3.

The AI replies by... yes!  Putting down an additional 1250 on me, to get me up to a nice round 1500.

I haven't verified this... but it's quite a suggestive amount.  Guess what happens when you divide 1250 by 5?  That's right, you get 250... exactly one bid for each AI.

I'll repeat this with 2, 3 and 4 hard AIs to verify, but it very much looks like the AIs collude with each other.

Update:

Well, colour me surprised.  I made a few new games and sat on my ass for the first 14 minutes, waiting for the first pirate raid.  This time the AI not bother to bid against me... apparently having two scouts to my name put me beneath their notice.

In fact, none of them could be bothered to bid AT ALL.  I could play with the bounties to my heart's content, and there was not a single attempt by any of the AIs to intervene.  If I'm no threat, suddenly their own skins are no longer worth saving!

Just for the sake of argument, I tried your suggestion... I put around 2000 bounty on 2 AIs just before bidding started.  I end up with 2500 on me.

However, thanks to that large lump sum, I was able to easily verify who put it on me.  It was a 3rd AI that had zero bounty on them!  And he cashed in a pile of resources to make that bounty, too.

I'll second this observation - I did a 4 way FFA, 240 bid was placed on me so I did 250 on everyone.  I went to 500, so I raised one to 1000.

Me 490
AI 1000
AI 500
AI 500

The AI let this stick?

I'm so confused right now as to how the bounty mechanic works for the AI ... 

I wanted to bump this thread, as it sure is annoying.

Small correction/observation.  I played a game were I intentionally didn't bid and the pirates did default to me the first time, but then seemed to round robin between players as long as there wasn't a bid.  The game only made it for a few rounds before bidding happened, but that seemed to be the algorithm.

OP is right, the AIs do not seem to put bounty on each other anymore.  Back in Entrenchment, AIs used to focus on their 'main enemy'.  If someone bid on you, you could throw bounty on one of the distant AIs and they'd usually get pissed at their neighbor instead of you.  Now throwing bounty of any of the AIs will always get them to throw it back on you.  With this and other issues, might just be best to wait for another round of patch changes before turning the pirates on again.

Second that!

I have been noticing this too. And it pissed me off that if I placed bits of bounty on each AI they would automatically outbid me together. Having given it some thought, I think this is intended on higher diffculty levels.

Spraying bits of bounty in FFA games was always an easy way to avoid pirates. In a 3 player FFA for example you could place 250 on each of your opponents and watch them outbid each other. Now, you end up with 500 on your head. This seems unfair because placing bounty against AI is no longer "anonymous", BUT it forces you to concentrate bounty on one opponent in order to avoid a pirate raid. As a result you have to pay more regular attention and invest more credits.

Placing bounty on several AI will ALWAYS backfire. You can no longer cheaply avoid pirates by doing so. Your best chance is to place bounty on one of them. This will start a duel between the two of you (since other AI seems to stay passive) leaving the AI better chances, since pirates are much more devastating now.

SO, to tell a long story short, when it comes to pirate attaks, it's human player against AI as a whole! It takes a while to get used to, but after having figuered this out, I think I like the greater challenge. I would welcome a different solution in the future... but for now: "Bring it on!"