If this is allowed for adults, I see no reason it shouldn't be for children.
Let the adults opt out of pain but let children suffer?
Sometimes I find it weird that some questions are even questions.
I agree with you all the way but like I said, to make that decision as a parent? Most parent will opt out and hope and pray for a miracle but at some point I suppose you will want to do it. Just don't know how you are going to live with yourself afterwards. At least my kids are grown up now.