It's a good rule. None should discount it. I can't remember gunning within the last 45 years when there's been alcohol around, period. But I think alcohol and guns depends on circumstances. I hunt with friends.
Let's say I was on the barrens hunting with newf and his friends and we "b'iled the kittle" and shared a libation after walking our legs off. It's social, companionable, part of a distinct island culture. I'd be pleased to be part of it.
I wouldn't feel I had violated a credo in the company of responsible men.