That isn't true for Spore. Even though it stated that in the game manual, after release EA has confirmed that you get only one account per copy. That can be doubly frustrating, especially for shared systems or those who are used to multiple accounts already. At the very least, the spokesperson for EA who confirmed the situation did say that EA is aware people want to have such functionality. Whether or not they are considering changing their policy remains to be seen.
Still, this isn't nearly as bad as it could have been. If you recall, earlier in the year it was discovered that Spore was going to be released with some heavy DRM, which was changed after a lot of negative feedback to EA.