That would be a strange system...
So they sort all scores
- give gold to the 1st one
- give silver to the top 25%, with a minimum of 4 players...
- give bronze to the top 50%, with a minimum of 2 players...
I don't know... I've been looking at ProcessEmergency_WorldCrisisPopup and GetSortedParticipants, but I didn't manage to crack the logic.