I agree and this is one of the reasons why kids should be exposed with parental guidance to gambling for gambling awareness' sake. Keeping the kids blind about gambling is one of the mistakes we should correct. A person must develop gambling knowledge in order to tackle and avoid the negative effects of gambling. The more knowledge a person has on gambling effects, the more resistant he is to gambling addiction. Aside from that, an informed person will never hesitate to contact medical experts whenever he sees signs of gambling addiction.
Letting children know about gambling through friends without their parents knowing is also their parents' fault because they give their children too much freedom to interact with their friends without the supervision of their parents. Children will easily catch or understand something from what they see through their friends or adults so they can imitate it easily. And if it's about imitating adult gambling, it won't be good for kids. So every parent should understand what their children's needs are and not just try to fulfil what they want.