On the contrary, this is my whole point. There is a big difference between simply copying the game save back and forth and in doing so, exploiting a loop hole and somehow modifying the code contained within the game save. If duping cars involved modifying the code, Sony would be well within their rights to come down with the ban hammer and close those PSN accounts. (Although it would be a very heavy handed action) What I have done, what a lot of people have done, is NOT a violation of the EULA. At least, not expressly so.
This is why a lot of people had an issue with the birthday glitch. Because in that case opening a sub account with a fictitious birth date IS a violation.
Exactly, the whole point of a backup is to restore it at some point. Any cars that you have given away to a friend in the timeframe between backup and restore WILL be duped, it's inevitable. It's not a flaw, it's a feature (or at least a regular byproduct of restoring a save).
The issue is in the intent. This is going to open a huge can of worms.
But there is a HUGE difference between Gifting something, then using a backup because your savegame went bad for whatever reason, therefore "accidentally" keeping your car, and specifically and intently creating alternate accounts for the purposes of doing it. It is a flaw in the programming that the car trade data isn't recorded online (or some other preventative measure) so if you did restore a backup it didn't take the car from you again. By knowingly exploiting that flaw you are violating the agreement.
This is nothing new. People have been doing something similar with games on the PC since the dawn of time. For games with only 1 save slot for a profile, back up your save and then restart from that point again if you screw up. The difference in the past is that doing that really affected nobody but your own playtime, so as much as they didn't want people to do that, it wasn't worth the time/effort/money to stop it. Just like "copy protection" on old PC games which required finding a word on a page in a manual. They knew anyone could just photocopy it, but its just a deterrent, to go much further (especially at that time/tech level) becomes not cost effective.
Now this has the potential to affect others play by flooding the world with cars that PD intended in the game design to be exclusive. They tried to put controls in the game (remember originally you couldn't back up your save file probably for this very reason) that failed as they naively believed people were just looking to back up their save games so they lifted the restriction. To try to appease both the people who are pissed off everyone and their mom has an X2010, and the people who legitimately want to back up their game, they have (or will) add a new restriction, maybe its just a precursor to a better one like keeping the gift data online so that you lose the car even if you go from a backup, but thats just not ready yet.
Pretending you're the same as someone who doesn't know any better than how it works is no justification. If you overhear at a business meeting that your company is going to tank tomorrow so you short sell 10,000 shares based on that info, Then your friend who just has a bad feeling does the same thing, you're the one whos gonna get locked up. I know this is an extreme example but playing dumb is no excuse.
Finally I'm not condemning you for playing the game however you want, I'm just tired of these threads of people trying to justify their actions as if you stole some diamonds but need a legal loophole to get out of it. You did it, big deal, I don't think you're gonna go to hell for it, and based on the rampant much worse cheating in other games you're not gonna get banned from PSN for it like MS did on the Xbox either. Trying to justify yourself through crafty wordsmithing of the EULA is not gonna make the price of coffee any cheaper, or change the fact that PD can do whatever they want to keep the game experience how they intended it.