.......I must say, we really are getting to the point of us vs them here.
This is a child and a bathroom. What is the big deal? You are supposed to be Canadians for crying out loud.
OTOH - Grandma seems to be a real pain in the neck and is possibly one of those people who gets her way simply because nobody wants to deal with her. This martyr syndrome of constantly pointing out the child was a........well child and urinated on her seat might have flown under the radar. Now the kids name is out there. One day some little boy will fancy this little girl and google her name. Then all h*** is gonna break out at school and the rest of the school year will be a real cakewalk for her.