A few (okay, okay, more than a few) years ago, I took my two daughters, then ages seven and five, to the playground at our local park. My seven year old was very proud as she was able to read the sign with all the rules to her sister. "Do not jump on the merry-go-round when in motion." "Go down the slide while sitting only." "Only one child on a swing at a time."
There were about twenty rules and the girls promised to obey them all, if I would trust them and let them play without Daddy standing by. They said that they were too old to be watched and their friends would tease them, calling them babies if Dad stayed. I made them promise to be good and obey the rules,
and went over to the picnic area and began preparing our lunch.
When it was time to get the children, I decided to watch them at a distance for a while to see how reliable they were in following my instructions. I found that they obeyed most of the printed instructions. That is, all but one.

They would get on the tall semicircular slide and go down head first or backward. Angrily, I picked up the children and took them over to the posted regulations and made my seven year old read it aloud, again. Then I asked the girls what they had to say for themselves. My five year old answered immediately, "Don't be silly, Dad. No one uses a slide rule anymore."