The blind screen is one of the difficult plays that basketball officials are called on to adjudicate.
The rule philosophy is, that if an offensive player sets a screen on a moving defender, that screen should be set far enough away from the defender that if he or she had seen the screen he or she could have had the time enough to stop and change direction and distance enough to stop and change direction, thus avoiding contact with the screener.
The distance by rule doesn’t have to be more than two strides and depends on the speed the defender is moving. The time is not spelled out and presumably is left to the judgment of the covering official
Contact on the screener, when the screen was “blind” or set out side the visual field of the defender, is often significant and can send both the screener and the player being screened to the floor.
If the blind screen was set legally (time and distance) any contact that occurs on the screener should be seen as incidental.
Offensive coaches often do not see it this way and are not in tune with the rule.
They want the defender who they screened from outside his or her visual field charged with a foul.
The rule book does not see it that way.
Below are two articles from Rule 4-40 that cover the blind screen situation
When screening a moving opponent, the screener must allow the opponent time and distance to avoid contact by stopping or changing direction. The speed of the player to be screened will determine where the screener may take his/her stationary position. The position will vary and may be one to two normal steps or strides from the opponent.
A player who is screened within his/her visual field is expected to avoid contact by going around the screener.
In cases of screens outside the visual field, the opponent may make inadvertent contact with the screener and if the opponent is running rapidly, the contact may be severe.
Such a case is to be ruled as incidental contact provided the opponent stops or attempts to stop on contact and moves around the screen, and provided the screener is not displaced if he/she has the ball.
If an official does charge a defender who crashes into a blind screen with a foul it must be because the official thinks that the defender did not try and mitigate the contact. In most cases, however, these plays should be seen as incidental contact
The clip below shows a typical “blind” screen that was ruled as incidental contact.