For WordCamp Toronto 2011 and 2012 we held our after parties at nearby restaurants. Alcohol was available, but food and socializing was the focus. Plenty of tables and (relatively) quiet music created an atmosphere where people could come together and have conversations.

If people wanted to get their drink on, they were free to take off and bar hop around the area. Many did just that.

I don't see the need to remove alcohol completely. Just don't make it the main focus. It's not a kegger, it's a WordCamp.

...though a WordCamp Kegger would certainly have an appeal as well. But I digress. ;)