Proper guidance is very important and I think it will also depend on the culture of your family, because in my country most of the parents didn't force their Children to leave their home even if they already on a legal age since we are family oriented, and parents are really responsible.
I agree that family customs also have influenced,
Guidance from parents is the first defense of our children. Giving them the right information and provide right example will let them
understand the risk that awaits them if they exposed themselves to gambling.
Underaged can exposed to gambling easily because of the advance technology that we have right now, we can't blame them for that since we give them the access to online, what we can really do is to spread awareness, and educate them as long as we can.
The big problem that most parents are facing right now, with the technology that gives easy access to anything, gambling addiction is very possible to happen to our kids.
Responsible parenthood not only by providing shelters and foods but also to provide good guidance to our kids, with the knowledge coming inside our own premises, we can lessen the chance exposing our children to gambling if we are keeping them busy in other task or family activities that will attach them closer to us.