Edit: please don't correct actual life experience with a quote from Wikipedia.
United Club is the name of their "first class" lounge, as people incorrectly refer to them. Those United Club Lounges have complimentary booze [1]. And no airline is going to allow a passenger to board who had obviously consumed the amount of alcohol you're referring to. I know: I practically lived at the T3 United Club lounge at O'Hare for many years, I was traveling so much. Not as much any more, but when I've been delayed significantly and I'm super-stressed because I'm speaking at a conference or something, I still occasionally get a day pass.
The United lounges you're referring to are considerably more elite, and most travelers don't even know they exist. Again, taken from actual experience and not a quick perusal of a Wikipedia article.
American's "Admiral's Club" [2] no longer offers complimentary liquor.
[1] http://www.united.com/web/en-US/content/travel/airport/loung...
[2] https://www.aa.com/i18n/travelInformation/airportAmenities/A...