I always thought government in exile was somehow related to whether the conquered government had any Theater level HQ alive when they surrendered. At least, the one game where a non-Allied Greece went into exile (a major pain, btw), the Greece Theater unit survived. It's difficult to see if the theater unit has any bearing on the government going into exile or not, as most of the time minor countries tend to join the Allies pretty early on, and being in a faction seems to increase the chances of exile. France and the Netherlands routinely goes into exile, but frequently both surrender before that last unit is killed. My guess -- the Theater level leader is the highest ranking official and tries to reform the government. At least from that aspect, it makes some sense to me.
It certainly makes sense that the chances for exile would be keyed to the date of surrender. It would probably be easy to code.
But it wouldn't surprise me if the game had several elements (faction membership, date of defeat, and surviving units / leaders) affecting the chance of going into exile. Or the defeated nations political relations with other countries. It is so difficult to isolate factors when a random number is involved.
