I have one thing to say to those kinds of parents....Fuck yourself. It is not a companies job to stop your kids from wanting their products. Why don't you grow a set and tell them you. YOU are the parent, YOU are the adult. If your kids are fat (baring an actual medical issue) it is YOUR fault. I am sorry if they are whining or whatever, but its YOUR job to deal with it, not McDonalds.
So in closing raise your own kids and stop trying to make others responsible for you being a lazy and shitty parents. If you dont want your kids to get fat then dont buy them things like McDonalds all the time.