But if your child comes to you and say "Dad, I have won in a lottery, why dont you go and collect a million that I have won for us", you would go and take money, instead of acting that you are disappointed for your child gambling activity and leaving prize at casino.
Here is another example. Everyone know that a lottery is a form of gambling. Many food and beverages retails constantly create lotteries with bicycle, playstation, vacation. Idea of such gambling is buy more products, increase chances to win. I dont think that parent would mind providing his details to get a prize from such lottery.
Everyone is going to act to be decent online but the reality all parent will go and take the money first because money is everything. The highest the parent is going to do is to warn the child and that's it. The generation of parents that we even have now don't care about the things their child do not to even talk about money that is involved. They will gladly take that money and might even encourage the children to gamble more if they can make a million from a jackpot.
I don't care about the quantity of the amount the child won, I will clearly stand for him or her to get the money maybe after that we can talk about breaking the rules about gambling. No way my kid will gamble without my knowledge, if they do that means they did it in my absence and will answer the reason why they do it. The thing is that it look kind of nothing until your kids don't want to do anything about life again except for gambling that's when the parent will know it's a very bad thing.
That what I have been said previously, no matter what people post here, they will take money anyway. They will even feel happy about that, and with high probability be proud, that their child is so young, and already brink money to family.
I am no difference, I would help my child to obtain the prize. But then I would figure out the details how he managed to win. If its from participating in a lottery, organize by brand, then its ok. If its from gambling, I would let use money only when turning 18 or will take full control of those money management.