Can’t help it, this machlokes between Popa and cshapiro is making me laugh out loud. I do agree with Popa though.
Popa-
Your words are mashma that there is a level of tznius which is halacha. Are you talking about an objective standard, i.e. no matter what the societal norm is, there are certain areas which must be covered l’halacha, as Sister Bear seems to claim, or are you talking about something based on societal norms? Because I have been wondering for a while if there is any makor that tznius in halacha is anything but the latter, so if you hold the former, please enlighten me.