If a defending player is lying in behind the ruck, the attacking team has in my opinion won the contest at the play the ball, and if the ball is purposely or accidentally thrown at him, it should be a penalty. Barring a genuine injury, the player should be making every attempt to get out of the way.
Agreed but getting out of the way depends on the situation. If you try and stand you present a bigger target than if you lie on the floor. Therefore you are trying to get out of the way you cause more of an impediment than if you remain motionless.
Players can't disappear, so they have to try not to interfere from where they are
Earlier in the year in Super League there were instances where players just threw balls straight at players who were lying motionless on the ground to win penalties. These were deliberate ploys to win penalties.
The RFL looked at this and said that penalties would not be awarded if the defender was not interfering and that looking for deliberate penalties was against the spirit of the game and was unsportsmanlike conduct. Since they made that ruling, no one has tried to do it. Problem solved.
The NRL has it right. Players who are not interfering and the ball is thrown at them...... play on