Rule Of Thumb Exception ...
 

Great "exception" interpretation.

I 100% agree with Camron Rust by rule, but would love to see a NFHS interpretation of such (similar to the necessary "step on but not over the division line" interpretation).

Split Second, Don't Blink ...
 

Reminds me of my extremely rare scenario where a player dribbling in the frontcourt very close to and parallel to the division line steps on the division line for a split second “between” dribbles and then continues to dribble in the frontcourt. His hand is never in contact with the ball for the split second his foot is on the division line. Note: The division line is not defined as one of the boundary lines (there is a "carve" out for this being a boundary violation on only an endline or a sideline).

https://forum.officiating.com/basket...ml#post1054108

That is irrelevant to the backcourt rule (9-9-1), which mentions "frontcourt" and "backcourt". Those terms are defined in Rule 4-13.

Meaning it is a backcourt violation since there was team control when the player stepped into the backcourt.

Backcourt ...
 

Good point. Agree.

So, I won't use the term boundary anymore.

Backcourt 9-9-1: A player shall not be the first to touch the ball after it has been in team control in the frontcourt, if he or a teammate last touched or was touched by the ball in the frontcourt before it went to the backcourt.

The player never touched the ball and the backcourt at the same time.

And the player in question had player control (not an interrupted dribble) as well as team control.