The sorts of factors that make for "defection" are not really accounted for in the current intelligence model, though. There was a huge difference in the contentment of the populations in the East and West during the Cold War. Lots of people wanted to come to the West from the East. Only a very few bothered to defect to the East from the West. If you've got twice as many tech levels as your opponents, and all your worlds are "jubilant" then you have a pretty high "standard of living" in your empire. What would motivate your crews to take a sleek modern warship and run away to the Gronk Empire where they don't have indoor plumbing in most cities yet?
The same goes for planetary rebellion. If you're doing a good job managing your empire then your own population, at least, ought to be almost rebellion proof. Conquered races, or races who represent STILL EXISTING empires outside of your own, are another matter entirely.
[This message has been edited by Baron Munchausen (edited 08 January 2001).]