I generally play every second game (gigantic map genius level) with the Altarians to exploit their ridiculous tech abilities and this time decided in the one in-between to play the evil Drengin.
With plenty of planets to settle, I was able to use the evil ideology tree to boost my production and then get my free transports and was soon merrily slaughtering my neighbours. (getting 2500 gold and 15 ideology points every time I took a planet).
One of them was the Drath and at ,move 77 they surrendered and transferred their remaining assets to some other civ (I play without the hara-kiri option). So I made peace and took some resources and 1000 gold and waited for them to disappear next move.(which seems reasonable to me given that they've lost but not given me anything).
However, this was a big mistake since on the same move - or in any case before they disappeared - another civ helpfully surrendered to them. In the course of the next 15 moves several more did too and they now have 85(!) colonies though of course since they started form scratch not many ships or much infrastructure.
Of course, I'll declare war again when I can - which is I believe after 20 moves so move 97 or 98 but I do think that this mechanism - which to be fair I've seen before of course - is pretty odd. And what if they were a pragmatic civ or much smarter than this AI is and managed to found lots of pragmatic planets so that they could then invoke the 50 moves of peace before I could redeclare?
What d'you think?