My 10 year old helped me brew last weekend; we had a great time. She and her 13 year old sister have helped me bottle before, but this is the first time either one has shown any interest in helping brew. Her interest was prompted by boredom and just wanting to spend time with me, but before long she seemed to find it interesting for its own sake. It was a great afternoon; I hope she helps me again.
We also make wine every fall with another family. Some years the kids are too busy playing to want to help, other years they're very into it. Their favorite part is helping operate the wine press (and when they were little, playing with and making a mess with the pressed grapes!)
Like others have said, I think this may help promote a healthy attitude about alcohol. In our home, making and drinking beer and wine is just a part of life. There's no great mystique or allure about alcohol, no taboo either.
Would some people find this inappropriate? Probably. After all, some people think alcohol is bad in and of itself.