Dodece is very likely correct, his idea at least has merit. It wouldn't take many people saying "it would read my game disc" for the issue to be blown into a "disc read error" scandal, especially after a similar thing happened to the PS2. It is very likely that a few people returned their 40GB PS3s being ignorant of the fact that it wouldn't play their PS2 games.
Help! I'm stuck in a forum signature!