Coaching box restriction after a T

[bainsey]

Originally Posted by AllPurposeGamer

The only thing that is illegal under NBA rules is for an offensive player leaving the court on the endline, for the purpose of setting a screen, in one's frontcourt. It's a violation and the ball is awarded to the defense at the free throw line extended.

Is this strictly an NBA rule? I believe no player can go out of bounds like that in NFHS, though there's not much point calling it if a defensive player does it (unless, maybe, the ball is loose).