Discussions

I hate to bitch but something has been nagging at me all nite.  
I work at a local resturant and was in charge tonite of a large group of people that came in to eat. I believe they were a team of some sort, there was a large group of parents a a large group of teenage girls who were all eating together, some were in families but some of the girls were without parents.  
Everything ran fairly smoothly and when everyone got up to pay, mostly seperate, some of the girls paying for their own meals, some parents paying by the family, most of the people were happy and appreciative.  
When they were all filing out, one family stayed behind to finish their meal with a few of their members who came later. When the lady came up to pay, I mentioned two dishes had not been paid for and described the two girls who had ordered them. I knew they had been sent out and eaten because later I cleaned up the mess and remembered the faces of who had eaten them.  
The lady mentioned that the two girls i was talking about had come without parents, she paid for the meals and said she would bring it up when she got back to the hotel room.  
About an hour later, another lady from the group came back, very upset. She couldn't understand why we had made the last lady pay for these two meals. She claimed it was my fault for not asking the girls to pay (even though about 20 of them came up to pay at the same time and it was hard to keep track) and demanded that we refund the money to the lady who had paid for them.  
Is this really fair? She got two free meals because two of the girls she was looking after left without paying. Is it just me who thinks this isn't right?  
We eventually gave her the meals for free but it's been bothering me all nite. I would love some feedback.