Players can no longer use the ready check feature if they have generated any enmity on a monster. If a party member who has yet to generate any enmity initiates a ready check, the ready check confirmation answer for players that have generated enmity against a monster will automatically be submitted as “No.”
So let's say in CT everyone gathers at first fight.

I'll say I do this for simplicity, but could be whoever. I look around, everyone seems ready, I pull.

Someone else who hasn't generated enmity yet initiates a ready check.

So then it defaults to saying I'm not ready cause I have enmity on one of the mobs we're checking to see if we're ready for?!?

Makes absolutely no sense at all.