There was a Watchtower article which talked about large weddings, which wasn't a good thing to do. You were supposed to have a 'wedding director' to make sure that no one over imbibed, that the music wasn't too loud and so forth. There were articles in the 1980's that discussed how JW's shouldn't have costume parties as it encouraged people to behave licensentiously.
As Jim stated, it was often brought out that large gatherings were verbotten, as you couldn't guarantee what people were doing during and after. Look at all the JW illustrations that feature gatherings, only a small few are there, the women dressed in dresses, the guys in dress slacks and someone seems to always be playing a guitar...
Sorry, I just realized that I posted this thread under the wrong topic, sorry!