Activision had permission to use "Welcome to the Jungle," but according to court documents obtained by Radar Online, broke its contract with Rose by including imagery of Slash in the game and offering music by Velvet Revolver as downloadable content. The juxtaposition "exploits the prior association between Slash and Guns N' Roses, promotes Slash's and VR's (Velvet Revolver) separate interests and includes VR tracks as available downloads, all of which was and is directly contrary to the contractual obligations of Defendants," according to the filing.
Indeed, Rose's filing asserts that Activision explicitly promised not to use images of any former members of GnR in the game. Even more surprising, Activision EVP of Music Affairs Tim Riley is quoted as saying "Come on Beta, you can't believe everything you read on the Internet" in response to rumors of Slash's inclusion heard by Rose's rep Beta Lebeis."
Whether Rose's claims of treachery on Activision's part turn out to be true or not remains to be determined, but one fact is incontrovertible: he is really, really late in noticing.