I'd say a bigger issue is with smoke and noise. Whether people like a glass of fruit juice, a glass of wine, a sparkle of champagne or a mug of beer it shouldn't really matter. But as WordPress is a publishing platform and hence attracts both writers and geeks, articulate conversation is a priority for almost everyone. Short live sets of not particularly loud music might add a cultural and party atmosphere without killing the social interaction.

On the other hand, if WordPress aims to be the platform of choice for party-poopers, banning alcohol, flirtation and fun would be a very good start.

PS. Some great comments above from judi, suriel, fwolf. I've just come off of three months of teetotaling (wanted to reset some habits, was quite busy). During that period, I certainly didn't want to stop attending events where other people were enjoying themselves or to stop them from so doing. There's lots of people out at high profile social events not drinking or drinking very minimally. There's no reason that alcohol at events should degenerate to a frat party. Ambience mainly depends on the venue and not whether the party is dry or not. I thought we'd solved the prohibition issue back in 83 years ago.