@garyackerman

Years ago, I visited a school with the publisher because that school (and their national chain) wanted to use my books.
Publisher: "How often do you teach X?"
Teacher: "Maybe 15 minutes a week, just the basics."
Publisher: stares.
Me: stare.
Publisher and I: stare at one another.
Publisher: "But... how can you test their skills then?"
Teacher: "We don't do tests. We have an 'accept all' student intake philosophy so, most aren't talented anyway."

I refused selling them my books.