1. It wastes "good witnessing time"!
I would have to go with this option. It would have been seen as frivolous in that it wouldnt "further kingdom interests". Oddly enough they were always encouraging that brothers and sisters talk together by arriving early and staying later. However, the hovering zealots always made sure it was about kingdom interest, heaven help the youth group found talking about video games instead of magazine placements. Although as soon as elder righteous looked away you can be sure that is exactly what went on. I remember sisters organizing a lot of such get togethers after bookstudies but there was always an excuse, such as just finishing a new book or welcoming new ones to the book study group that were just moved there.