So you are saying that she check-in and was asked to pay XXX number of dollars over the amount she was billed and paid to Disney?
Or she checked in and realized she didn't have the plan and had to pay for it at check-in? That has happened to number people here on the boards, who thought they had added
free dining or a free dining code to their reservation, but got there and found out that they didn't. You aren't supposed to be able to add the dining plan at check-in, but in cases like this costomer service can do an override and add it, but you do have to pay for it.
If it was the first scenerio, Disney would have been in violation of som FTC statutes and she could have fought it.
Also, she could have gotten the discount if YOU had called and added her, her children and thier room to your reservation because it would not have been a new reservation, but a modificaion. You could have even paid with her credit card to make the change to your reservation. I have had to do this twice, in regards to a free dining reservation, when, at the last minute my mother-in-law decided she wanted to go. The fd code I used to book had long since expired, but I was allowed to add her to the reservation with no problem and keep the discount.