Illegal back row attack
 

Can the R2 call a back row attack? My understanding is this is a positional penalty. What if the R1 is visually blocked in viewing the foot/feet placement (say by another player occluding the view of the foot relative to the attack line).
Is this considered good teamwork? or should the R2 'pass' on signaling this infraction. As with other sports the bottom line is to get the play 'right' and not be so concerned with who makes the call. I understand each has their primary responsibilities, however, I would be glad that the R2 has 'my back' when it looks like I either did not see the foot placement or simply missed the call. In NF, it does not seem to directly address this situation.

As the R2, I will take a step forward and provide the "discreet" illegal back row attack signal we discussed prior to the match. If my partner sees me and chooses to pass or fails to glance in my direction after a reasonable amount of time, I will drop it.

Identifying and whistling illegal attacks and blocks falls under the responsibility of both the first referee and second referee.

If the first referee does not acknowledge your discreet help as the second referee, or does not recognize the fault has occurred, the second referee must whistle it.

The only exception is if the first referee clearly disagrees with your signal (says the player was behind the line, below the net, or the ball was partially below the plane) or the fault in question. If that's the case, prepare to defend, second referee.

The key is to discuss this in your pre-match. As second referee, I always ask my first referee "At what point do you want me to whistle illegal attacks, illegal blocks?" This tells them that I'm aware that it's a shared responsibility, and that I'm prepared to whistle it if I have to.