Have you noticed that some posters purposed punishment, limitation or something of that kind to a underaged kid who had a big win. Why punish a child, when its parents fault that let underaged to gamble, its their fault that they havent paid enough attention to what their child is doing. Parents are responsible for their children fully until they turn 18. Punish yourself instead.
You have a point about that, it's the parents fault why their underage kids were able to gamble. Giving free and easy access to the gadgets and also to the internet.
If they have just allowed their kids to watch tv then this won't happen.
But at some point, this give the scare to their kid that they should never do it or else, they'll get beaten.