Okay, playing Devil's Advocate...
Why is this person taking these kids to McDonald's without their parents or the school system's knowledge? You put the child on the bus assuming that they are going directly to and from school, no stopping, do not pass Go, do not collect $200. End of story. While I agree that the mother's scenario for disaster is a little out there, it is true that in case of emergency the school system and parents would have NO CLUE where to look for the bus because it is no longer on its route when it is in the McDonald's parking lot or stopping at the RiteAid.
As a teacher and former daycare center worker, I have had all of the safety stuff pounded into my head and for good reason - all of our rules have come out of some horrible tragedy where a child was lost, hurt or even killed. We don't go anywhere, even in our own building, without letting someone know. There are specific plans and ways of doing things so that if there was an emergency, the first responders would not be relying on my help (what if I were the one needing their help?).
And what if the parents didn't want the kid eating at McDonald's? What if the kid has a health condition and is resistant to following the dietary guidelines. If you had a diabetic child grabbing a Coke every morning on his way to school without your knowledge,, that could seriously affect his medical care.
Heck, I have to get a permission slip for everything from photographing my students to giving them certain foods. I cannot believe it's okay for a bus driver to swing by McDonalds on a weekly basis without getting the thumbs up from anyone. And to change the pickup time to do it? What about a kid who misses the bus because they're out there at the regular time?
I think the whole thing is a little nervy myself. I'd be ticked too.