Good parents always have a way to keep a strict eye on their children and they don't run from their responsibilities.
yes when they are still underage the role of parents is to limit things to maturity before their age. and because this is related to money so teach them to be responsible for all the decisions they make. there's no way parents can limit what they do on the internet and that's for sure, but they can do much more than that.
If the parents can not watch over their children, do not give them gadgets and make them spend their time alone because that can make them visit the site they should not be. It is better if their parents stay beside them if they want to use gadgets so parents can know what they're doing.
It is important to teach them how to manage money at their ages so they can do better when they grow up and will not try to spend their money without something they do not really need. They can know that they do not have to gamble to make money when they grow up and it is better to save their money on other things.