Look. This is a matter of CMs being @$$h01%$. Pure and simple. They don't have to scan the APs or anything of the sort. We're standing there as a
family. My DD is seven, for Christ's sake. She doesn't have a job and she doesn't have any money. Where do you think she gets her money from? Mana from heaven?
The CMs glance at the AP and ID (IF they bother to ask for it) and they
choose to give the discount or not. Again, plain and simple. It's not like they had to retain
any proof of why they allowed the discount. Any CM refusing my DD the discount in my scenario can... well, you can imagine what they can do.
I don't give a tinker's kitty why Disney developed the policy. If my DD is standing there to make a purchase and she meets the criteria for purchase, she is entitled to the discount, and I don't care if Jesus Himself descends from Heaven and hands her the money.
You can defend Disney and their policy until you're blue in the face. I don't care. I'm right and you're wrong. Look up consumer protection laws.