[toong]

Maybe I'm a cynic but that could be the point ?

Make it too cumbersome for your users to put an mp3 from their pc on their iPhone and they might just buy the song again from iTunes ?

[sbuk]

No, just ill-informed. You can re-download your purchases (which are DRM free) from the iTunes store on to your device. There is absolutely no need to use iTunes to manage an iOS based device. Not for registration, backing up or adding media.