NFHS Rule 9-3
Note: the dribbler has committed a violation if he/she steps on or outside a boundary even though he/she is not touching the ball when he/she is out of bounds.
Why is there a debate on this? This might be the most clearly written rule in the rulebook.
If you're looking to give a T on an OOB dribble, you're trying to take over the game too much.
I always call a force-out.