All you people who say "They can't" are being incredibly stupid. It's just a number, and that number has to be stored somewhere. Either it's stored client-side (stupid), or server side. If it's stored client side then you can remove it yourself, or in the more likely event that it's stored server side they just need to change the record in the database.
Now, it's entirely possible that it's too difficult to change it. That's understandable. But "impossible"? No. They made the game, they made the leaving system, they can fix/change/manipulate it on a whim.