It makes no sense to refund to 50% of the guys and those who got robbed wont be able to get refund.
So the simpler solution is to give every one CDT's
But do you understand that it is exactly the way of thinking that made CDT tradeable at 10% of the ICO price now on the exchange? Refunding those who would like to be refunded + giving the tokens to all the rest would make the token valuable. And currently it is trading at 10% ICO price here. Thanks to people who think like you.
https://etherdelta.github.io/#0x2fe6ab85ebbf7776fee46d191ee4cea322cecf51-ETH