Not all users will have access to all of Forza 3 due to multiple DVDs.

[JaggedSac]

Hmm...lets see if that means harddriveless 360s cannot play or that they wil be disc swapping. Doesn't seem like something a MS first party game would enforce. Halo 3 will put data on the hard drive and stream it but that doesn't mean an Arcade cannot play it.