Is Showing Nipples Through Clothing a Faux Pas?

Yesterday was National No-Bra Day. And numerous ladies freed their ladies in celebration of this auspicious day. But a little tell-tale issue comes up. This column from Dear Prudence points out the issue.

It's pokies. Yes, often when you go braless you may have your nipple outlines show through your blouse. As a matter of fact, in the fall it's a foregone conclusion that they will be obvious. 

So, what to do? Wear a bra and be uncomfortable, or not give a damn. After all, women have breasts, so people should get over it. What do you think? Is it rude to show, or just relaxed?