Well as you can see
here there are macbook upto week 22 with this problem (week 22 being June 5th to June 11th.
But then again, remember that those built on Week 23 have only been used for a week, 1.5 week tops, which wasn't enough for my macbook (week 21) to show any stains. After 2 weeks of use I could see a slight shadow of a stain and now 2.5 weeks later it's quite evident there's a serious stain here. I tried to take a picture a few days ago and you couldn't see it but now you can. I will post the pics in that website I gave above so you can see.
I foresee that at the end of this coming week, we will have a lot more week 22 macbooks and probably one or two week 23.
I have been advised by my family's attorney to take this case to the Trade authorities in Spain and see how this is taken from Apple, in general the customer protection laws in the European Union are quite strict.
Just one thought: I realised about this problem almost a week ago, as I said, it was a failrly fain shadow-stain. Then I started take VERY GOOD CARE of my laptop (ok, notebook :D). But it got worse. Way worse. No cleaning stopped the progressive damage of the plastic. Oh, and washing my hands twice as often as I used to * did not help either. Also, no cheetos involved here. Hate them
* Note: I have to wash my hands very often because of my work, I'm a scientist and need to work in an sterile environment so the cells cultures don't die. So, I used to wash my hands very often, now I do it twice as often to keep my macbook from further damage. Guess what, it's not helping. APPLE