Creating open communication will require awareness from the gambling addict to want to open himself up and accept the presence of other people who will help him cure his gambling addiction. But if a gambling addict denies and doesn't want to admit that he has a gambling addiction, it certainly won't work and he will still have difficulty curing his gambling addiction. His denial may prevent other people from knowing what a gambling addict should do and how to help him.
But it will depend on the people who want to help him because if they still care about the gambling addict, they will try various ways to divert his attention to gambling. Maybe they won't do it openly because it can keep gambling addicts away. But they will use other approaches to make the gambling addict aware that he has other things he can do.
I agree with the fact that it depends on the people who wants to help the addicted gambler cure his addiction, firstly coming with a judgmental approach make the gambler less responsive to solutions, when you judge him and exact all blame on him for been the reason everything happened to him/her, the gambler becomes less Open and will conceal most information that's need to help for fear of been judged and blamed again.
Approaches matters a lot as this will determine to a good extent how responsive the gambler who needs help will be responding to solutions offered them. They have to be treated with care and a good level of confidentiality especially for one who has hidden their gambling habit for a very long while, if they don't sense confidentiality they will open up less, but if the security of their information is sure they will speak up more.
Gamble addiction is not a plague and has solutions so we should learn to treat people who suffers this addiction with love, care and hope to get better after. I think professional help dose the job better because they know how best to offer solutions that will be tailored to various levels of addiction and how well to fix it fast enough.