Dave, you make some excellent points, but it is clear that you making the point from a male point of view, which is ok and we women appreciate that. But let me speak for myself.
Non celebrity women (like myself) do dress braless more often than not, when we go out for a fancy dinner, night out with the slinky black dresses, that are either low cut in the front and/or in the back.
Nobody complains about that, either other women or men, it is just accepted by everyone.
Now, I for one, dress braless during the regular everyday day, but I do not flaunt it, never, never.
Now, on occasion, one might see my nipples protruding out of my top or blouse in the summer time, but those are rarities and quite often, I put a tape or other commercial nipple pads over it, so I do not invite stares to my breasts rather than my face.
So in summary, a certain way of dress behavior is the norm in certain situations, like an award show, and other times, in the office, there is a different norm.
Very acceptable to me, and so far, nobody has made a negative comment to me for being braless 95% of the time. I go braless for me, not to show off my nipples or my breasts.