This is quite a tricky problem to solve without storing information on a central server. MMO's like WOW have solved this by requiring that the game save is stored on their servers rather than on user's machine. Until GT moves to such a solution, I don't see how it can be done.
The problem is that GT needs to provide offline capability. If they start requiring an internet connection, they will lose a significant portion of their market. I don't think Sony will go that route. (my educated guess)
The problem is that GT needs to provide offline capability. If they start requiring an internet connection, they will lose a significant portion of their market. I don't think Sony will go that route. (my educated guess)