Like someone else mentioned, it is the liability issue. Besides, as a parent, I would want my child to be with me - if given the chance - to a) enjoy with the child and b) keep the child safe for the duration of the eclipse (the safety and liability issue is absolutely NOT the "couple of minutes" of totality but the couple of hours leading up to and away from it).

That said, neither of my kids' schools closed, but they didn't want to leave school to come with me to watch totality. So, I drove alone about 600 miles each way and had a wonderful viewing of the eclipse. :-)