Some of my neighborhoods are playing gambling in front of their children and guess what, I'd see their kids playing with them already. We thought that educating them earlier could help them understand what gambling is all about but the results are too opposite, we are grabbing them to gain curiosity and try.
Yes, there is a right time for them to learn about it, and when they are already at an illegal age where we believe that they are capable enough to understand the whole concept of gambling.
This doesn't need to be done or what this means is that your neighbors don't need to gamble in front of their children because it will trigger their children's curiosity to find out more and try. And this happened to his children because they saw that it was an interesting game. Maybe later they will find out more from the internet if they can access the internet easily.
Now they already know about gambling but hopefully, your neighbors can give them an understanding that gambling is not a place to make money. These children are not old enough or are not suitable to be familiar with gambling because it can carry over until they grow up. But hopefully not.