This field-trip permission slip from FAILblog is a great example of how ignorance is perpetuated by families, despite schools' best attempts at amelioration:
"Note: Just to let you it is not that we don't believe in things like that, it is just misleading when you talk about it being billions of years old, when we all know that the world is only about 6,000 years old. So why would I pay so that you can misslead [sic] my children, your world is just a revolving [sic], ours has a start and an end. God created the world. He created animals and man all in the same week. It was also Adam who named all the animals, they will do the essay 'Rock and Minerals' but it might not be 5 pages long, and about billions of years, it will be according to the Bible."
I checked Wikipedia for the prevalence of Young-Earth Creationism, and it's truly disturbing:
Yikes! Just imagine what all those home schooled children grow up thinking. At least, her/his kids are being exposed to different ideas in a public school. Even if he/she doesn't allow them to explore those ideas. Sad.