[just another ref]

Originally Posted by Camron Rust

The NFHS has established that touching the floor outside of marked lane space is equivalent to leaving that space. There is no reason the same concept doesn't apply universally.

One very good reason. It's not in the book.

With the enter-on-contact requirement for FTs, the rebounders can easily time their entry and don't need to lean in...

But they do it anyway.

and if they do such that they touch the floor before the ball hits, they'll still be on the floor when someone else gets the rebound. What advantage is that? If they touch the floor way before the ball gets there such that they have time to get back up and be ready for the rebound, they couldn't possibly have been anticipating the ball hitting the rim/board. And what advantage is that?

Nobody wants to touch the floor. Obviously no advantage there. But if they do so, they are not allowed to reset without penalty, as specified in the rule, for the players in the lane spaces only.

If this is the intent, and perhaps it is, another clarification is in order.

"Once the ball is at the disposal of the shooter, neither the shooter nor any player in a designated lane space is allowed to leave his spot by contacting the court outside his own area."