Joffe stated it best here. If the PS3 does log certain info, that may be how Sony would be able to find out. No one is really sure yet how this can be backtraced, pun intended. We will have to rely on what happens in the next few days and listening to reliable peoples info of what they did to not get banned once the actual first wave happens. Problem is that there are so many unreliable people that will make shit up.