Motherboards fail more often than you'd imagine, liquid damage being a common cause. The chips may be fine but since they're part of the failed motherboard Apple won't do a thing to recover the data. Unlike removable storage where you can move it to a working machine.
Do you have a source on that? The mac users I know are especially worried about data loss because of the high rate of other failures on their new MBPs. One of my co-workers temporarily lost some of his work because he hadn't pushed his changes to git and his computer had to go back to apple for repair because it wouldn't boot. He got the computer back the next day, so all was well, but it makes you wonder.