Against a press, the 'lead' is at midcourt and I'm on the back baseline...so he has the front of the action and I have the back. As play moves forward, so do we. You call your 'primary' unless there is overlap (3-man crew)...if you get some raw official who wants to call everything he sees, all he will do is follow the ball and ignore the off-the-ball contact. If this rogue official makes calls in my 'primary' it means 2 things...(1) he's ignoring off-the-ball play and (2) making the other official look ignorant. Should an evaluator be there observing both (or all 3 officials), and assuming the rogue official got every call correct, he would be ripped apart/demoted for not doing HIS job. ..which is to know and officiate his primary. Just because you see contact doesn't mean there is a foul...which is why you don't make someone else's call(s). They have a different angle and perspective that MUST be respected. It's this way with every sport. Have you ever seen a 2nd base umpire call a player 'safe' at 1st base? NO! It's not his call. Or a home plate ump call a base stealer out at 2nd? No...it's not his call. Should a Biology teacher grade your Calculus quiz if they see it in the teacher's lounge? No, it's not his subject. Should a coworker tell you that your wife has nice ta-tas? No, unless your a member at DCC. Make sense??? If you're still confused, I'll let the Rock explain it...
