> the occupants were engaged in some nefarious activities; therefore the curtains are left open to show that the occupants have nothing to hide and are engaged only in wholesome activities.

That sounds utterly dystopian. Whose business is it if we want to shag in the morning?

It’s also completely self-defeating. Nobody can prove that they never did anything that someone else would disapprove. There are solid reasons behind the "innocent until proven guilty" principle.