Grits with Grandparents

My MIL got all dolled up to go to breakfast with the kids at their school only to miss most of it. Someone that I will not name, told the kids to go through the regular breakfast line instead of the special line while I signed in. My MIL is hard of hearing and just followed the kids. Turns out all the kids didn't get to eat the special breakfast b/c of this. It upset me b/c they were done eating before my MIL got near the food. They were ready to go and antsy. I had to force them to wait on her. Once she sat, they were a bit better but ready to go. All of this could have been avoided if the person would have asked IF they had a grandparent there and not assumed that they didn't. This person knows who we are, too. I do not think it was to be mean, she just assumed they wouldn't have anyone there for them when they really had 2 people there.