I was under the general impression that there are no circumstances where a defensive player can run over a player with the ball, especially one who is not dribbling. Then this happened.

Player A4 has the ball in the high post position and has not yet put the ball on the floor and has shoulders parallel to the basket and has pivoted on his left foot (the one closest to the basket). Player A3 curls around the high side of A4 from his backside and is soon followed by B4. A4 (with the ball)pivots out of the way of A3 but gets run over by B4 who was never seen by A4. The call is made that A4 has set an illegal screen and is given a foul.

Is A4 obligated to keep both feet set with the ball in hand while 2 defenders close in from either side mearly because a team mate passed by?

A blocking foul can be committed by the offense or defense. Most often it is committed by the defense. Illegal screens are blocking fouls committed by the offense. Rarely is it ever committed by the offensive player with the ball. However, you described a situation where a blocking foul could be committed by the player with the ball (pivoting into the path of a defensive player). Just because you have the ball does not give you the right to pivot over the top of people or step into defenders as they pass.

But it wouldn't be a block call in this situation, would it? You would still have a PLAYER CONTROL (not to be confused with charging). Thus if the defense was in bonus they would not shoot.

Yes sir, if the "team mate passed by" and used the player with the ball for a screen. Possessing the ball does not give one special privileges, not afforded to others. In fact, the play is becoming more and more prevalent and should be whistled.

Good call!

Blocking is simply the illegal contact that occurred.

The type of foul is a PC foul.

The fact that it's a PC foul doesn't change that it's blocking.

FYI

dont have my NFHS rules but NCAA rules specifically state

Art. 4. A player with the ball may be a screener and shall be subject to the principles of screening.

So it is an illegal screen by player with ball.

For what its worth this is where NCAA/NBA have it right and just have the same foul for team control/offense and dont ever have to shoot 1+1 !

Wasn's trying to change the blocking call, just could imaging seeing a bunch of officials signaling a block on an offensive player with the ball.

Is that a problem?

Maybe i did not emphasize the positioning of the player with ball adequately. He was in no position to see the defender of the teammate and the so-called "screen" was not a deliberate act to free up a teammate but rather a repositioning to better get off his own shot. The secondary defender collided with the high post just after the post player had pivoted away from the secondary defender (whom he couldnt see). If a player with ball in a high post position can be made to be a screener simply because a teammate passes in the vicinity, that means that the player with the ball and already closely defended is obligated to look all around him to make sure that no teammates might curl around him and if they do, he MUST hold both feet, cannot extend any part of his body or make any move at all while a second defender approaches who at any time may decide to double team him. Heaven forbid the post player does not have perfect balance at the time one of his teammates curls around the backside for according to the rules as it has been interpreted here, he cannot pivot nor do anything else but to just sit there and wait for the double team to come and steal the ball from him.

I thereby feel that a screen, especially one by a player with the ball, should at least have to be a deliberate act which it was not in that circumstance and that would leave the call somewhat up to the judgement of the official.

Unfortunately the rules don't agree with your feelings. The act being "deliberate" or not has got nuthin' to do with anything. The player with the ball has to allow the moving defensive player "time and distance" to avoid contact- usually up to 2 steps. If he doesn't, it's a block. Simple as that, and got nothing to do with whether the player with the ball did it deliberately or not.

If you are an official, I suggest that you review rule 4-39, especially 4-39-2&5.