Personally, I think that gambling or not everyone decides for himself, but to hide it, at least from your closest people is not the best solution. In addition, very often it turns out that the people around you know more about you than you imagine.
It is difficult to ask for a helping hand when you hide from the closest people that you play gambling. It is not that hard to become a gambling addict. If you ask any gambling addict how he got into such a situation, it is very likely that he will either not admit that he has any problems, or will say that he does not understand how it happened.
Denial is one of the traits or should I say attributes that follows an addicted person, not all gamblers have the will power to admit that they are actually suffering from gambling problems and hiding a problem just makes it harder because the solution to the problem too will be far from coming. In all the times I have being with gambler who have such problems, I have come to realize that it's actually a common thing for such people but the only way to get to them is to act directly to the problem without you waiting for them to admit to the addiction issue.