Regarding when an alliance is double zoning,
Should double-zoning be announced by the head referee? Any referee? The emcee?
Since double-zoning isn’t actually a rule violation I don’t think there should be any standard to announce it.
But on the other hand, would alliance A be given an advantage if the emcee announces alliance B’s double-zoning even though A didn’t notice? Or anything like that?
Could it also be said that announcing double-zoning should be actively avoided since it presents an opportunity for an unaware team?
What you are talking about is covered in the Emcee guide.
Sportsmanship
Emcees are responsible for adhering to the highest standards of sportsmanship and serving as a positive role model for the participants. Modeling good sportsmanship includes announcing the game in a non-partisan manner, not suggesting game strategies to the teams, and fostering a positive, collaborative event environment.
One could argue that the emcee is merely reporting what they see on the field. This would help spectators understand what is happening in the game. Conversely, it would alert a team that is not paying attention.
What I would listen for as an EP is that the emcee is calling the plays consistently. If they do report on the double-team then I would want them to cover it each time it happens in a match.
I also trust my head referee to advise the emcee if they think they are not following the Sportsmanship policy above.