I have long been troubled by the definition of chatzer in the sugya of kisui rosh.

Let's set the Chasam Sofer aside, and assume that a chatzer is a chatzer. Most of us assume that Rashi's pshat (according to the Ritva) is that women leave their hair uncovered in a chatzer because no one will see her.

Doesn't this contradict the entire yesod of the first perek of Bava Basra (as well as everything we remember from Eiruvin about multiple houses by definition being part of a chatzer) that it is impossible for a user of a chatzer to predict or preclude the visual intrusion of the members of the chatzer? Decades ago someone told me of an unnamed rosh yeshiva who in fact maintained on this basis that a woman whose hair is uncovered at home need NOT run to cover it if an outsider walks in, because the bayis cannot be more chamur than the chatzer!

Y Adlerstein, Los Angeles USA