I know what you mean about the yuk factor, but it really is not that bad. "wag bags" are now required for everyone on Mt Whitney and Mt. Shasta. You are given bags when you pick up your permit and there is a special disposal can at the trailhead. The bags also are useful where you just have to move the poop to a more appropriate place. Sort of like picking up your dog's poop in cities. A plastic bag over the hand is helpful. I agree you should keep up the effort to teach proper place and burying, but having an emergency back-up is wise. In the big picture it is a small issue and nothing you want to have discourage your kid from backpacking. When I had a problem with my kids, I always said, "they do eventually grow up". Todays big problem disappear, and a new unexpected one crops up! Welcome to the world of parenting!