I don't follow any of this...
You mess up a car buy thinking you can tune 2 with the same tool. 'Unlocked' isn't what most think it is. It's not simply flashing 1 car back to stock to flash another, it needs to be 'formatted' also; which is software most don't have anymore (only people who do are those who had/have and old PRP disc ;) and SCT.
So ghost data from the old car gets written to the new one, Car bricks, you go into panic mode. I don't know where this public callout comes from. I've seen the same thing happen before and SCT has bent over backwards to help, for free mind you. Actually happened to a buddies truck as we where tuning it. Sucked and we had to tow it home. He got lucky and had an X3 and the tech just did a remote reflash and it was back to normal.
Thing is, he's also using a tuner that was used. IIRC he said they also reformatted the X3, so it should be good now.
Anyways, always be wary of used electronics. That's just common sense.