Is very hard to even hold a child to not do such a thing because you have no idea where he might learn it from and as long as they have heard that someone won a huge sum of money, it will trigger them to go and try if luck will be on their side. Parents can't hide it from them, ok what if a situation where the child have never seen the parents gamble but they saw it on TV or by chance they find themselves in a gambling area and coming back home to tell the parents what they encounter outside, what do you expect the parents to do? To me is best to tell the child everything he or she needs to know as long as the child is up to 18 then he's an adult, by so doing you'd point out the negative part of gambling first before the positive side of it and is only a reasonable child would get the message of the parents.
With the technology that is currently developing rapidly, it is easy for everyone to learn various things, including children who might ask how to bet on a football match, even if we don't tell them, there is a possibility that the surrounding environment will teach them such as with their own circle of friends or they themselves who are looking for a way because now everything can be searched for and found and then we learn it.
Children who get good lessons or good education from their parents, for example by telling them what to avoid, then it is likely that the child will not do something that is risky for themselves or others. It is different from children who cannot accept their parents' education well, it is likely that they will deny the education from their parents that they have been taught. Even so, as parents we must still provide the best education for our children, because it is impossible for parents to educate their children in the wrong things.