I think i got pretty luck here but you guys let me know. Bought a Rev A macbook air on craigslist for like 900 a few months back, machine came with apple care and a few extras. Then the enter key was sticking up slightly more on one side so i figured i have the support might as well take it in. The key was sticking up from a pervious repair. So the took it and fixed it. when i got it back the keys didn't light up and the sound was gone. I called and when i bought it back they gave me a new Rev B macbook air with an extra power adapter. Needless to say i was very happy. I have heard of this happening to other people is it starting to become common?