The three northern European countries have had a small number of first party titles switched to cardboard cases due to the shortage of normal plastic ones!
"A statement from officials at Nintendo of Benelux (Belgium, The Netherlands and Luxembourg) indicates that a shortage in plastic cases means that the packaging for a number of titles will be switched to a Game Boy Advance style cardboard box of the same size.
The new cases will include an apology from Nintendo and an invitation to order a plastic replacement when stock levels return to normal in December. Only specific first party titles will be affected, including Super Mario 64 DS, Mario Kart DS, Animal Crossing: Wild World, Tetris DS, New Super Mario Bros. and all four variations of Nintendogs."
One for the collectors out there