[classicman]

Schools introduce children to things that they would otherwise not be introduced to or experience. To me the whole experience of "going to school" is an integral part of the maturation of our children. For them to go to school less is not a positive in any way, shape or form.
Additionally, taking this time away as a "last resort" probably means a lot of those other things have already been canceled or removed. Field trips and additional extra curricular activities have been getting cut for years.

I think that homeschooling is a totally separate issue. Most people who homeschool their kids do a fabulous job. The rest are typically religious zealots.