
I hear a very small violin playing...
The relevant portion of the AppleCare T&Cs, for those playing at home:
"Apple will either (a) repair the defect at no charge, using new or refurbished parts that are equivalent to new in performance and reliability, or (b) exchange the Covered Equipment with a replacement product that is new or equivalent to new in performance and reliability, and is at least functionally equivalent to the original product. "
http://www.apple.com/legal/sales-support/applecare/appmacnaen.html
Half the time refurbished gear tends to run a little better and longer, depending on where and who refurbished it, and what was wrong with it originally.