Contrary to popular belief, Apple has not warrantied the polycarbonate top case for their MacBooks. I just got off the phone with Apple and they said if you are still covered by the original or extended warranty, they will replace it for free. However, if you are no longer covered, you will have to pay $200 for a new top case. I personally think this whole situation is being handled poorly. The MacBooks are prone to cracking, it is a design defect. Apple should replace the top case for free even if it's out of warranty. It's their fault this is happening. Sigh.