My folks took myself and my sister out of school for a 3 month trip to Europe over 35 years ago; best thing to *ever* happen to me during school. I learned a hell of a lot more than an education could have ever provided. We had homework with us, but the teachers basically said "Let them live - this is an opportunity to experience the real world."
Sure it wasn't high school, but the experience of visiting so many different countries, different cultures and exploring life outside Australia is one I'd never trade in; we remember it like it was yesterday even today, and often bring up things our folks have forgotten or weren't aware of.
I don't have kids, but if I have the chance to take my nieces on a similar journey, I'd do it in a heartbeat. Some things you just can't learn in a classroom - life isn't about rote learning, it's about experiencing it for yourself and what better way to do that, than by travel?
So they say - it broadens the mind, and I thought that was what life was all about; opening oneself to new experiences and enjoying the differences cultures the world over have to offer.
Schools need to understand that sometimes it's the actual living of life that makes the person, not how much they studied at school . . . . . . . .