Here's the skinny. One of the four requirements for a back court violation is team control. There is no team control during a throw-in. During a period of no team control, team control is established by a player establishing player control. Player control is defined as holding or dribbling a live ball inbounds. A2 tipping the ball is not the same as holding or dribbling it, therefore no player control established, therefore no team control established, therefore no violation.
I can get into more detail if you want.
