[greymule]

For JO FP and SP and adult modified, rule 7-3-C lists 8 circumstances under which the batter can leave the box.

Number 3 is "if forced out of the box by a pitch." You could argue that the batter in question was avoiding being hit, regardless of her faulty judgment. The rule also says, "leaves the batter's box and delays play," so merely leaving the box momentarily and getting right back in is not a violation. Example: nobody on, pitch goes back to the screen. As the catcher retrieves it, the batter steps out of the box and takes a practice swing. She returns as soon as the pitcher gets the ball. That is not a violation.

I would say the girl could jump out on every pitch with no penalty. Whether the coaches should remove her from the game is solely their decision.