Have you noticed that the Operatros when you press the name of an Op you can see that he or her is an Operator because they have this thing under the name:
So that eveyone knows that this player is an op of Zombie. So my suggestion is that if we could do it with Trusted players. We do have the title:
Maybe we could put it under our name and like that People will know we are Trusted on the Zombie server.Some People Put the Zombie Trusted On there spoiler but not everyone look at the spoiler and they dont know that he or her is a Trusted.