It does occur. I have a range on my property + several years ago a lady came out wanting to learn how to shoot. She was a Tx. transplant from Boston + had never been around guns. She listened to instructions (women are the best ones to teach) + her form was correct but her shots were constantly off horiziontaly.Verticle was pic. perfect + that gave me the clue. Up until that time I had never encountered anyone who was cross dominant.In the 80's when I was building rifles I came up with a design that was a bent stock to simplify that esencially allowed the shooter to put stock to shoulder but the lay over would put the dominant eye down bore center.Odd looking but functional.