Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
Is complete segregation between men and women best whenever possible?
This is most often the case. Sometimes people do not completely understand what is most beneficial for them, so they may need some preparation to understand that. Allah’s command regarding dealings with the Mothers of the Believers is sufficient for us: If you ask them for something, then ask them from behind a screen. Allah then says: This makes for greater purity for your hearts and theirs (33:53).
These explicit Qur’anic texts are sufficient. Before the verses of hijab were revealed, some men inclined towards praying in the back rows (closer to the women) and others, out of fear for their religion, strove to pray in the front rows. As a result, Allah revealed: We know those of you who hasten forward and We know those that lag behind. Surely it is your Lord Who will gather them together; for He is perfect in wisdom and knowledge (15:24-25). How can this not be enough for someone? Here there is a specific command: Say to the believing men that they must lower their gaze… and say to the believing women that they must lower their gaze (24:30-31). Anything which assists in implementing this command can only be praiseworthy. We also know that it is permissible for a group of men to address a group of women so we should not jump to prohibit that which the Sacred Law has not prohibited but at the same time we should not belittle that which the Sacred Law has recommended.