I've had my new 13" 2012 MBA for about a week, and occasionally I would notice something under the 'C' key preventing it from being pressed down. So, I turned on the backlight and could see it was small piece of plastic rolling around. I removed the key and it turns out that piece of plastic was part of one of the clips that attaches the key to the keyboard. The key is still functional, but seeing as the computer is brand new, I'd rather have it at 100%. After talking to the Apple Store, my options are to either bring it in and have the keyboard replaced (which they do on-sight), or get a replacement laptop. They apparently do not have individual replacement keys, so if I opt for the repair, the entire keyboard is getting replaced. I'm also concerned that something might get dinged/scratched/damage during the repair process that I won't notice right away. The downside to getting a replacement MBA is that my current one has the superior Samsung display, and I'd risk getting an LG in the replacement. Furthermore, since I upgraded the RAM, I'd have to wait for a new one to get shipped to me.