I work at a startup that has an amazing office, with a full bar and eight taps for draught beer. This makes it easy to knock back a few while coding throughout the day/night. I'd dare say, that the availability of free drinks coupled with a culture that promotes drinking as a social lubricant is just about the most tempting atmosphere possible.
Surprisingly, people do not take advantage. I think some less mature people may like to brag about how much they can code whilst drunk, but it's just like any other drug: If you can do X, Y, and Z incredibly well while under the influence, odds are you'd do even beter while sober.
If you can "get shit done" while drunk b/c you're no longer afraid of the awkward situations, odds are you'd do even better at handling them sober.
We've never had an awkward situation where someone checks in epically bad code due to being sloppy-drunk that I'm aware of, but that's b/c people are largely self-policing and they realize that what you an manage to do drunk, you can dominate sober.
I don't wish to sound like a prude. We do enjoy the refreshments, but usually after-hours, or at least when doing exploratory R&D, perhaps playing with a new design. To do your best work on the most important projects at a startup, you really to to bring your "A" game.