[Adam]

Originally Posted by JetMetFan

So this is me becoming the Devil's Advocate: if the thrower and defender are that close that the thrower is able to push the defender, one of two things has happened:

1. The thrower has moved too far forward during the throw-in, which is a violation (I'm basing this on the throw-in taking place at any time other than after a made/awarded field goal or free throw).
2. The defender has moved too close to the thrower, in which case it's a warning or technical foul on the defense.

False choice. In this case, only one player is prohibited from breaking the plane. And even if he breaks it, we're told to call the foul if contact is the immediate result of the violation.