Fair Ball Rule in Baseball: Batter Safety and Foul Ball Definition

Question
We had an incident the other day where a Majors (12 year old) player bunted a ball that bounced off home plate and then bounced up and hit him in the arm.  As per rule 6.05, the umpire called him out for being hit by a fair ball.  Does this rule apply when in the batters box?

Answer
Tim,

If a batter remains in the box and is hit by a fair ball, it is a foul ball.  However, should the player leave the box (all it takes is one foot completely out of the box) and get hit a second time, then the player would be out.

-Martin Hoover