Agree 100% with @Vertigo, also agree with @Acrofales, better guild management tools could help with any confusion in setting up 0 damage. Guild leaders should be shown what members are under age, and can not participate in chat. It's usually them who don't follow the rules, because they can't, and the guild leaders are left wondering who can and can not see chat.
Most of the problem here is that guilds full of 80+ level members are too strong for the Rancor raid. I think it is great that EA continues the Rancor Raid, but it is sorely in need of a higher tier and better rewards. But for now we need to work within the constraints and set the necessary limits so the most Han shards and rewards can get distributed to as many guild members as possible.
But making it easier to get rewards is not the way to go. It's silly. You should be asking for devs to make it harder.
