An internal memo from AIG was leaked (you can find it here) and in it they argue that they have to pay these retention bonuses because if they don't it's a cross-default on their part and they'll have to pony up billions more in payments to CDS counterparties. Are you effing serious! I've never even heard of a cross-default.
I think these assholes engineered it this way. How can we not pay these crooks to stay on and untangle the mess they've created to screw everybody over now? If these jerks are not paid they'll walk, and then you and I will be pumping in however many more billions to cover the cross-default payments! It's a lose-lose situation for the American taxpayer. You clever bastards!