Same thing here! After only a couple of weeks using my MBP13' I noticed the P key was slightly crooked but I managed to place it back carefully and decided that was not an issue. To my surprise it came off again and again intermitently. I could still use the keyboard normally but then decided to contact Apple Care to resolve the issue as it is under warranty.
When I took it to the service provider I learned they wanted to charge me $ 250,00!!! and that it was due to external factors, meaning it was my fault! and they would not repair it under warranty!
Again I tried to contact Apple Care but got the same position.
I think it is humiliating for lack of a better word to pay through the nose for such a computer and have no support regarding an issue which clearly comes from the fact that the keyboard are extremly poorly made. Mind you, this is my second MBP and the first one never ever gave me an headaches as the current one 2011 model.
I am being forced to resort to the local consumer protection league and will respect their and only their final decision.