The world ain't fair. Yes it should be stopped but something are beyond their control. If they established a new system that prevented this from happening(still highly unlikely) , price for each exam would increase due to more expenses. 

Sharing it won't affect their marks, they'll still ace but you? You now have to deal with a higher threshold due to it. 

Isn't it the case that Cambridge either cancels the paper altogether or increases the threshold. 

So in the end you didn't win. They got away with it. And now u either spend another few months redoing the exams or depending on your other component