If we allowed parents to remove their children any time a fact is taught that undermines some belief, the classroom would become a never-ending carousel of students coming and going. Some ethnic students would leave history class if a discussion of slavery and its economic benefit to Colonial America ensued. Then the population would shift again as we enter biology, and the fundies pull their kids to keep them from learning that God isn't responsible for how creatures are today. Following that, the New Agers yank their kids while astronomy is discussed, and the 24 or more constellations in 'the Zodiac'. Then some brief chaos as the Breatharian kid has to be monitored during lunch, and then the National Socialist's kids have to be watched while Art class discusses African animistic symbolism in art; then, during Music class, all the Fundies leave again, since we'll be studying non-Gospel music for a bit...
And so on, and so forth.
And when testing time rolls around, and no one scores more than about 50%... what then? Oh, I know - drop all the standards, pass all the kids, and watch the world continue to slide into anarchy and chaos.
Sorry, Beth, but I'd rather see the government give all the faithful a huge wake-up call, teach the facts, and tell the families to get over the nonsense and the bull - if the kid misses lessons on evolution, flunk him on that section. Education shouldn't be about catering to faith, but providing a good, solid basis for the future of mankind.
Beth's idea is a PRIME example of the damage that organized religion has on the world - and I know I've said (or tried to say) it before: when ignorance is preferable to faithlessness, we've failed as a race, and it's time for the roaches to have their turn.