I don't know how we got on the subject of timed matches.
There is a difference between disagreeing on a call and requiring that both partners agree.
Think about it. You are at baseline, I am at net. Ball goes deep to you and you call it out. Opponents turn to me and ask what I saw. I am not sure because I didn't look, couldn't see, was screened by my partner. So I say "I dont know."
Opponents cannot say my uncertainty means I am not 100% sure it was out, so we do not agree so it is good.
Partners do not have to agree. They cannot disagree. Not the same thing.
-- Random Error Generator, Version 4.0
-- Master Moonballer