And when they see their parents gambling, they will come closer and want to know what gambling is like. Moreover, if they have money on the gambling table, they will ask, which may make them even more curious to try it later with their friends. I can't imagine if these underage children were gambling with their friends. And even if it is a small bet, they don't deserve to do it because they can become addicted. After all, they will find that gambling is fun, especially if they can take home some money. You must be careful, especially if they ask their parents for more money. Parents must always pay attention to their children and provide understanding so they do not take the wrong path.
This shows that you dont have kids, or dont pay much attention what they do during free time. You see the situation from adults point of view, but kids (I mean like real kids, not teenagers) dont care much about money. They have parents to solve all that "money moments". So when the kids see money on the table, first they get excited if there is a lot, but often quickly lose interest to it. You know, the kids rarely measure things different than adults. They rarely use "money" to measure things. When they see something, it is big, small, shiny, tasty, red, heavy and etc. They dont measure things as "that cost 9.99", "this is 100 bucks", "wow that cost like 3 my monthly salaries", "this car cost a million".
Regards your phrase that I have bolded. When I was a kid I bet 3 chewing gums that I can swim the pool faster than my friend. From your point of view, I with this bet I did something bad and I did not deserve to even place that bet. But, I believe, when you was a kid, you did similar bets either.