As mentioned above, the most common mistake is setting the board down rotated 90 degrees. There must be a light colored square in the right corner of each players side.
Another common mistake is to set up the king an queen switched. Remember, the queen is placed on the matching color square (white queen on light square, black queen on a dark square).
As far as setting up boards 180 degrees off, the best solution is to purchase a "no-notation" board. It will never be set up incorrectly. As players gain experience, they no longer look at the side notation anyway, they "know" the name of each square by heart.
Alan S.
I'm not sure that would make the game illegal. I have been playing so long that boards did not routinely have rank numbers and file letters marked on their edges. I would find it strange that USCF and FIDE would make a game "illegal", and thus need to be restarted, simply because markings outside the 64 playable squares are inaccurate.09/23/20