My mother. Her non-JW husband belonged to the Legion (for ex-military). She would go with him --- a real no-no for JWs. She went with him and would buy one drink for herself while he would drink until he was plastered. Meanwhile she would sit there nursing her one drink. What no one knew was that she carried a flask with here and would go into the washroom and have sips from her flask.
Now I would never have guessed this. But one day she proudly showed me her flask and said she didn't want worldly people to know how much she drank.
I have never seen her drunk, that was the husband's job as a binge drinker. But I also have never seen her go through an evening without a few drinks. She thinks she isn't an alcoholic because she doesn't get plastered. But just the fact that she hides her drinking and drinks far more than anyone realizes puts her dangerously close to the line to having a real problem