Here's another tangent on that question...
If a computer program was used to randomize things, then it would seem logical to assume too that said program would randomly select 1 "orphan" car (the one that appeared only once).
On the other hand, if they were loaded by a human, did they randomly place a different "orphan" on the board each time? In theory, if you had 8 cars, and you wanted to save on the budget, if done by humans, they could more often than not set it up so the most expensive car did not match on the board.
Very interesting question...I wonder who would know the definitive answers to these?