I had a BF during my college years who was this way with booze.
A friend had gifted me a gallon (!!) of Kahlua because she knew I enjoyed relaxing with a White Russian now and then. So I figured I was set through middle age with that bottle.
I came home from work one Saturday and went to fix one for myself and found the EMPTY bottle still in the cabinet. Since the BF was my roommate, I knew he had consumed it all (and I hadn't even opened it myself). When questioned, his response was something to the effect of "hell, it was there to be drank..."
Needless to say, over the few years that followed, his drinking problem became blatantly obvious. He was the sort who was never able to have a "liquor cabinet".