What do you think is a good punishment for a referee that makes a bad call?

nothing? why should they be fined for a genuine mistake? how many people have made mistakes in their jobs or in school. reffing is a really hard job and they don't get as much credit as they deserve in my opinion. So just let them get on with their jobs! and plus isn't human error what makes the game more exciting, if every call was correct what would you and your friends talk about in the pub on a saturday night?