The change in policy is because of cheating, according to a Microsoft spokesperson I talked to.
"Microsoft goes to great lengths to protect the Xbox 360 and Xbox LIVE service from cheating, which is the primary purpose and use of these unauthorized MUs [memory units]," said the spokesperson. "Unauthorized MUs are not tested for compatibility or certified for safety and compliance standards and thus could damage customer’s Xbox 360 consoles."
This update does not affect the hardware's interaction with third-party hard drives and USB thumb drives. You can still store music, movies and photos on those devices and the Xbox 360 will read off them just fine. Licensed Xbox 360 memory devices are needed, however, in order to store (and move) profiles, game data, etc. Before, this was possible using the memory options provided by Datel and other manufacturers. Soon, it won't be.
"Memory Units without an official Xbox 360 licensed logo are considered unauthorized and are not guaranteed to work with your Xbox 360 console," said the same spokesperson. "All authorized Xbox 360 Memory Units are marked with an official Xbox 360 licensed logo. If you have specific questions about a 3rd party accessory, we recommend you contact that company for additional details."
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I didn't paste the entire article. Just the quote from Major Nelson. If you want to read the rest of the article click on the nice little link =)
