A total ban normally only forces the thing underground and makes it all the more wanting by people. Rather than halting the given issue, it usually breeds new ones. People should not be banned entirely; regulation and education proves better in the case, the government is really willing to defend people. Individuals are supposed to choose what they want to do including making some of these decisions which might be risky as long as they have been made informed.
I agree with what you stated that it will force people to go underground, but the result of people engaging in gambling would be less. With the government actively restricting people to engage in gambling and apprehending those who were caught, this will bring fear to the citizen and avoid gambling all in all.
The only people who will still engage in illegal gambling are either addicted gamblers or those who do not fear government regulation. So with the government banning gambling, I think it will not solve the problem with people engaging in gambling, but it will greatly lessen those who actively participate in it.
For the government to effectively enhance the effect of banning gambling, it must couple it with aggressive apprehension of those who break the gambling ban.