I understand that. They do still know that you have x number adults and x number kids and they can tell you at the point of sale that you cannot get x+1,2,3 or more adult meals because you only have x adults. What opened this wide up was their decision to allow
DDP users to use their credits for people not on the plan. That is what allows you to get adult meals with kid credits, because you can buy x+1,2,3 adult meals at one time. Since they do not keep the adult and child QS separate AT THIS TIME, it is a loop hole they have created. If/when they decide they don't like giving away adult meals for the child price, they will fix the system either by separating the credits or reinstating the "rule" of not using DDP for others not on the plan.