I have watched tons of games from youth 8u to the highest level collegiate, and there is zero tolerance of talking back to the refs. And there is similar zero tolerance for trash talking. You will occasionally see a yellow card and a man down situation (20 seconds in the box), but it's more likely you will get rolled (the refs actually make a rolling motion with their hands) and be out of the game.

Also with respect to diving, if you get a rep for diving in polo, there is no call for that. The refs just allow you to get mauled.

That said, the way polo coaches ride the refs is abhorrent. I don't get the extreme dichotomy between how players and coaches are allowed to behave.