Overruled!

You can quickly assess your status on the team by trying to overrule a call made by a teammate. It's obviously acceptable for captains to have the final word when someone on your team makes a questionable call. For those of us lower on the totem pole, it comes down to a combo of respect/reputation of rules knowledge if your teammate will accept your decision or stick with theirs (if the opinions are contrary to one another).

One of the more interesting unstated rules of Ultimate:
Player A and Player B disagree on a call. If one of Player A's teammates agrees with Team B, and makes their opinion known, Player A will change their call most of the time. There is a correlation with the respect/reputation of the teammate who disagrees with Player A (and the stubbornness of Player A).
"Even your own teammate says you weren't fouled/inbounds/stripped/humped!"

This definitely leads to a lot of players from Team A either not voicing their opinions on calls (if it's contrary to their teammate) or going the "I don't know, I didn't see the play" route. Especially those on the sideline.

Is this an effective way of deciding a call? Obviously not, as your teammates could be just as wrong as the other team.
But it does pose an interesting question going back to the essence of Spirit of the Game:
At Nationals in the championship game, in the last point, a teammate of yours is called for a strip in the endzone. You, standing on the sideline, get a 100% view of the play, and it was absolutely a strip, but a debate ensues. A "No Contest" from the defender (your teammate) will lose your team the game. Do you make your opinion known even if it will cost you the game and the title?