Can a legal pleyer "slide" down one space if that space is unoccupied by the player who should legally be there?

The player in the lane space nearest the shooter sees that the space down from him/her is vacant and just slides down there before the ball is put at the disposal of the free throw shooter. Not allowed in NCAA, but is it OK in National Federation? Rule 8 Article 3(F) is a little confusing.

Yes, it's allowed.

Burtis449,
If I was the player responsible for the shooter, I would not slide down to that open space, allowing the shooter a better chance for a long rebound.
mick

That is interesting that it is still allowed.

As of June of last year, we were told that no one
is to be allowed in the space nearest to the shooter.
So, in our case, it doesn't matter anymore. I also thought, correct me if I'm wrong, that this is now a federation high school rule.

NFHS rules mandate that 2 defensive players occupy the lane-spaces nearest the basket and that the two lane-spaces nearest the shooter remain vacant. Other than that anyone may take any spot that is not occupied by the team entitled to it by alternation.
Of course, the teams must still comply with the maximums of 4 defensive players and 2 offensive players along the lane.

NCAA Women: The spots are designated and cannot be filled by the opponent if left unoccupied.

NCAA Men: I'm not sure, but I believe that the same movement as NFHS is allowed.