Kids must focus at the schooll and following something they wanna to do at university, gambling, trading are something they dont need to be introduced to ruin their life, later if they wanna they can ask advices about and share their opinion, but kids must play their games.
Actually gambling can be learn by a child in schools thru their classmates and friends. Parents could not see them when they are at school or outside the house, so we can't prevent it from happening. What parents could do is to really make their child aware that it could ruin their life so when a child see and been pressured to gamble, they could still refuse it. Gambling isn't good for adult, so as for kids, they should not do it.