So I'm playing a game as Yor, crushing the life out of the Krynn as usual (they always seem intent on declaring war on me the second I meet them) and this time I decide I don't want to wipe them out, I just want to smush them down as far as possible before they try to quit.
The war's just about done, I'm saving at the end of every turn so that I can reload if this is the turn they quit, and then two things happen.
First, they bail, but, shaking their fists angrily in my general direction, they hand over their assets to their friends the Iconians, rather than me. Awesome!! Never seen that before, very cool. I almost left it at that - the Iconians are next on my hit list anyway.
But I didn't want them dead, yet. So I reload. And when I reload, even though it's still my turn, they surrender on the spot. And, this time, instead of the Iconians, they give all their stuff to me. This persists even after a client restart, unsurprisingly.
So, two bugs to report. First, I guess if you squash an empire down to whatever level they find unacceptable, save, and then reload, that empire surrenders as soon as you're loaded in, rather than waiting for you to end your turn (and thus preventing you from extorting harsh peace terms from them).
And second, in doing so, they'll hand their stuff over to the player instead of their AI friends - a (very mild) exploit, but exploitable nonetheless.
Now, I guess I have to go back to a 15m old autosave if I want to let the loonies live... but maybe I should play a game as Thalan, since apparently I've been missing out. 
Edit: Interestingly, in all 3 game states (pre-turn surrender, surrendered assets to Iconians, surrendered assets to me) I'm still able to enter diplomatic negotiations with the now-defunct government, offer them peace, and take all their technology. lol. Their icon is a space station
They disappear when you get the "Krynn defeated" message on your next turn.