People under 18 do lots of things that underage people should not supposed to do, why would gambling be different?
If they have the means and the money, of course
The problem is that the children are more aggressive and hence gambling should not be introduced to them. But anyways if they are gambling then they know what it means and the do's and dont's of gambling
Most kids have no regular income and they still rely on they parents to meet their daily needs. That's why people under 18 aren't allowed to gamble at most places. What if kids got addicted to gamble but had no money at all? We're afraid that they will do crime to get money to fullfill their addiction!