As we discovered today GT5: Prologue is kind of unshareable. Every 24 hours one person can play the game on his PS3 before an other person/ps3 can log on and play the game. It can only be played with the owner account (who paid it). Off-line you can't play the game so you have do be logged-on to the PSN network. This is against what sony's stating in the PS store. There it says that it can be shared on 5 different registered PS3 systems.