hitting on arms during rebound

[Kelvin green]

Im willing to bite and throw a monkey wrench in the works
(as if I have not stirred the pot already)

Take a look at Article 1. Verticality only has to do with legal guarding position.. and legal guarding position must be maintained.

In a rebound situation as first described. Who is guarding who? Did they establish and maintain LGP?

Rule 10 Section 6 Article 1 Extending the arms ... other than vertically so that the freedom of movement of an opponent is hindered when contact with arms occurs is not legal... The positions are employed in rebounding, screening, and various aspects of postplay.

I might buy that if someone actually raised their arms straight up and hit the arm there may not be a foul. However if they do anything but raise their hands or arms vertically would still be a foul.

As said before just because a player is in their space it does not give the player free reign to foul to get ball.