In other words, this is a 3,000 mile "executive car" that has never been registered yet but it's in the hands of a "3rd party dealer" who is NOT a BMW dealer? All BMW executive cars are sold to BMW dealers who bid on them. If there is a 3,000 mile executive car that was not purchased by a BMW dealer, then I would proceed with caution, as others have already advised on this thread.
It may be possible for it to go to the auction and still not have any problems with it at all but that would be the exception. You would have to have the car inspected by a qualified body shop or someone experienced in recognizing paintwork and/or frame damage before buying a car like this. I would never, ever buy a car like this sight unseen.
The balance of the original BMW 4 years/50,000 miles warranty and 4 years/50,000 miles free maintenance goes with the car to the first registered owner, so the car should qualify for that unless there is "some reason" the warranty has been voided, which may or may not be a consideration. In any case, as long as the car still has its factory warranty and you're going to be the first registered retail owner, you should get both the warranty and maintenance but that's something you should verify by VIN with BMW before finalizing a deal.
I think the bottom line is that most people would be a lot more comfortable buying a car like this from an authorized BMW Center. In fact, most people would completely avoid buying such a car from a 3rd party dealer.