I personally don't owe anyone a duty to let them know what I'm doing or not doing in this context. What difference does it even make in the first place? Will they support me financially in gambling or they will wish me well? Will there wish even translate to the outcome of the game?

Apart from my partner that I practically discus most of my life issues with, I'm a reserved person and unless its necessary, I don't even share my work outing with a regular person and gambling is totally out of the equation.