On Tu be’Av, they walked around in circles and did not realy dance.
Even though it may be only a middas hassidus to have a mechitza for eating, it is a very good and necessary chumra — because of the way a lot of women dress. Namely, they are dressed to kill. Even if it were not the case, it would be good to have it — “kol makom she’ata motze geder erva, ata motze kedusha”.