did you talk to a floor sale rep? Because they are half retarded and I swear none of them have any sort of training in any of the Apple's policy. When I was buying my first mac, two guys told me I can replace and upgrade the HDD myself without voiding the warranty in a 12'' PowerBook, and that ALL of their systems had the 7200RPM drives (including their laptops)... this was about the time when the first 2.5'' 7200RPM drives first came out...
ironically now when I go back to the store, I see one of them that mislead me has been promoted to a higher position... not a store manager, but some type of manager none the less...