I'm one of those guilty moms.
I let my 9 year old play with my 20D with 24-70 on it when we are at home. I set the shot up, and since I have to be in the shot, I let him shoot. Also, if you have a good tripod and a shutter release cord, that's a good way to introduce kids to the cameras more than just a point & shoot. They can have some understanding of what composition and exposure mean. My older sons can handle an slr without too much trouble now, they are adults and play with my old equipment. My younger sons are getting the 530A this Christmas and will have all the shooting they want with it. I even got them a 256 card so they can shoot 100 pictures without having to process them. They also have their own old computers to use to PP. Given a proper amount of guidance, kids are brave and very creative. I've been exposing my children to technology with accountability for many years now. I still yell at them, though, when they do something wrong, but giving them tools young when they are ready to have them is the way to go if you can afford the money and TIME. Never give the kids stuff you can't handle yourself.