Oh, this sounds like a fun way to raise circulation numbers. Imagine folks wandering the stacks, one guy with a slight slur in classic lit saying "You know, this Jane Austen chick ain't half bad to look at. I think I might take her home."
Then look into the next day. Patrons waking up in a hangover haze, surrounded by opened, tear-stained books thinking, "Man, this Paula Dean cookbook looked so good last night, but now I just want it out of my house."
I am just saying I am totally for drinking responsibly in the library. But not on the job. Think of the shelving disasters that happen sober. "Let's just pile them in the middle by color. Yep, that'll teach'em" hiccup.