This applies to the current debate about doing tafsiq on things that are forbidden within a school. Sadd al-Dharayi' is an important principle.
http://www.alahazratnetwork.org/modules/booksofalahazrat/item.php?page=5&itemid=186 Alahazrat's monograph on wedding rituals is a must in our times. Look how he says that though something is permitted, it isn't expected that people will stick to only that which is allowed; therefore it should all be stopped.
