I understand that gambling addiction is an extremely severe topic but these people have to understand that the universe doesn't revolve around them. If the emails really were temping it's in his best interest to just either unsubscribe manually or block their address entirely.
That alone IS PROGRESS towards curing problem gambling. Reject the convenience and any temptations that is dragging you back in...
Unsubscribing or ignoring is the right thing to do, this is part of the challenge of reforming or healing yourself, if you can fight the temptation then you are not dedicated to healing yourself from gambling addiction, Stake should address this issue it will have a bad effect and many players will have a second thought of playing more on Stake.com, especially those who are thinking of using the exclusion feature.