My favorite US festival, Old Songs, is not "dry." The Newman's Ale people (as in the Roberts/Barrand song) have had a sale truck there for many years.

Most US folk and bluegrass festivals have a "no alcohol in the concert area" rule, but don't give you any hassle about what you do in the camping areas.

I guess some of the major rock festivals are quite different - searching everyone's rucksacks, not letting you bring in bottled water because it might be vodka, blah, blah.   I won't go to such an event more than once, if that.

Peter.