This made me think of this new thread. How do we make sure that a point won by a player effectively goes to that player?Mention Wozniacki enough times and eventually someone will flip a coin and a picture of Jana Fett will magically appear in that thread. Speaking of Fett, what is she up to now? I checked and she's out of the top 300, so what happened to her? She can't possibly still be sulking about those two match points, right?
My suggestion would be a roll-over challenge, with a 1 point penalty. It goes like this:
A player will be penalized by 1 points if she gets 3 challenge wrong in a row.
After the penalty, her challenge gets reset.
If she gets a challenge wrong, followed by a right challenge, she gets an automatic reset.
This means the player will never run out of challenge but can't abuse the challenge system because of the point penalty.
If she gets 2 wrong challenges in a row, she'll think twice before her next challenge. If that next challenge is right, she "gets out of jail". Her challenge is reset.