And I'm not doubting you, Velho, but to all ... make sure if you are accusing, you are measuring from the white edge of the plate (not the black) to the edge of the batter's box line ... should be precisely 6".
I, too, have seen batter's boxes as close to 3" from the white edge in a Varsity game. The young coach's retort was, "It can't be wrong ... we use a template to draw our lines."
So sad ...