When my oldest was three, some dear friends of ours (graduate students) were moving out of town. We had a goodbye picnic at Gallup Park. They had two kids, and the younger one was (and still is) exactly one month younger than our son.
After we ate, the kids were off playing on the playground. We looked over, and found them doing something that we didn't like. (No, I don't remember what it was.) We intervened and called them over.
And as they walked away, back to the playground, we overheard their daughter saying to our son, "Let's not do that again."
I imagine that is how the Ann Arbor schools are feeling now, regarding the Dicken lunch bunch field trip.