If A-1's throw-in is touched by B-1 who is standing on the boundary line, did the official rule it a throw-in violation?

In this scenario, the official would rule that it was not a throw-in violation. According to basketball rules, a player who is attempting a throw-in must release the ball from the designated spot, and it remains in play once it is legally touched by a player on the court. If B-1, while standing on the boundary line, touches the ball after A-1 has released it for the throw-in, it is considered a legal play. The key aspect is that the throw-in must be completed without any violation occurring at that moment.

If B-1 had touched the ball before A-1 completed the throw-in, or if the throw-in was taken from an incorrect location, then there might have been a violation. However, simply touching the ball while standing on the boundary line does not automatically constitute a violation. This understanding helps clarify how and when a throw-in violation can be called during a game.