Not facing the opponent

[Rob1968]

Originally Posted by Snaqwells

He's entitled to a spot on the playing court. Not to the air space above it.

So, what do we do about 4-45-3: "The hands and arms of the defender may be raised within his/her vertical plane while on the floor or in the air."?

This statement, and others, intimate, and indeed indicate, that the vertical plane is considered in regards to contact between opponents, whether the opponents are grounded or airborne.

I still see the statements regarding verticality as applying to two subjects:
1) a player and his inherent right to a position on the floor
2) a player and his rights regarding contact with an opponent, be it a defender or an offensive player.

Where does one find reference to "a spot on the playing court" meaning "in contact with the playing surface"? Is not the concept of verticality meant to define the reality of movement by all players, in a game which intrinsically involves leaving the playing surface vertically?

So, A1 facing B1, with his back to B2, who has the ball, sees that B1 looks upward, and reaches upward, as if to receive a pass from B2. A1, thinking to foil the pass attempt, jumps, within his vertical plane. While in the air, B2 drives into the back of A1. Blocking foul on A1?...Really?