A short note:
I hone my sabre refereeing skills by looking at high-level bouts on youtube and calling the point before the real referee calls it. The thought behind that is that I will train myself to become reasonably fast at calling priority situations, and hopefully I will become better at calling the situations the same way as the top-level FIE referees doing those events call them. The assumption here is that if I can call the priority the same way as a FIE referee consistently, I am becoming better at refereeing.
To that end, I just looked at a team sabre event, refereed by three different head referees. As far as I could tell, those three referees differed in timing and allowed retrograde hand movement. The first means that a phrase that one referee would have called as an attack simultaneé would be called as an attack/counterattack – albeit a close one – by another. The second means that there is some leeway in how the hand moves during the initial part of the attack – a minor movement towards the fencer himself might not be enough to make the referee consider the attack abandoned. However what is minor for one referee is not always for another.
In the team event that I looked at, there were three referees, and it seemed to me that the fencers were confused shortly after each switch of referees.
The obvious remedy is to name one head referee and stick to that decision, and only replace that referee in truly exceptional circumstances.