Niddah 17: Intercourse During the Day, What is Hated by G-d, Privacy

After a long discussion about examination of cloths, the rabbis continue that discussion with a new Mishna.  In it, Best Hillel claims that women should examine themselves before and after each act of intercourse over the course of one night, and thus there should be light in the room.  Beit Shammai disagrees, of course.  Instead, women should examine themselves once before the first act of intercourse and once after the last act of intercourse over the course of one night.  

The rabbis consider several issues:

• whether a drop of blood might have been covered up by semen in a subsequent act of intercourse - this drop might be missed if an examination does not happen between each act
• Whether or not it is permitted to have intercourse during the day, as the laws of modesty suggest that we do not look at nakedness
• Whether or not it is enough to create darkness within the home, even by using one's clothing to cover the bodies
• whether exceptional circumstances, like being overcome with great desire, could permit intercourse during the day
• if the examination cloth is lost, whether the examination must be repeated 

The rabbis attempt to interpret the phrase, "everything is in the hand of Heaven except for the fear of heaven".  They speak of the angel of conception being available at night, and how this angel takes a drop of semen and shows it to the Lord so that G-d will describe what kind of person this will become.  We are also told that there are several things hated by G-d that are also hated by others, including one who goes to public drinking houses chats, or is short-tempered, or lives in the highest house, or urinates while holding his penis, or suddenly enters a home (for he could disturb those who assume privacy).

It seems that much of today's day is about privacy.  How private are the most private activities?  These are not hypothetical situations, but the realities of people's daily lives.  How do we understand what information can be determined by individuals, couples, rabbis, communities, or only by G-d?