Pushing the boundaries...

When you give a child a certain instruction to do or not to do something, you will see them try their luck to beyond what they are supposed to or not supposed to do. If a barricade is erected to limit their space, they would stand touching the barricade. If the barricade is a rope, they would stretch their luck as far the rope would stretch. If the barricade is solid, they would stand on the boundary and see whether if their action is remanded. If it is all quiet on the top brass, they may stretch their reach by stepping a foot out to test the waters.

This type of treading dangerous waters can also be seen in Hollywood and amongst teenage girls who are slowly getting comfortable with their body image and sexuality. In the 1940s, actresses were required to cover up till their necks without revealing the silhouette of their contours. Later, by pushing for changes, the filmmakers managed to get the censors to allow a little bit of cleavage. With creative thinking, they manage to bend the rules to show more and more as long the areolar was not visible. With liberal thinking of the society and demand of equality of the society, even a full Monty is no big deal anymore. 

Just like that in the music industry, when Elvis started gyrating his pelvis, the world thought that Armegeddon was nay. Looking at the present MVs especially those involving rap artistes, we seem to have come a long way.
And this is how undergarments have evolved to become formal attire.
But then... this type of thinking outside the box is the one that propels society forward. If we got stuck on to age old beliefs and traditions, Columbus would not discovered the New World, advances in ICT would not have materialized and A-bomb would not have been a reality.
Like in MGR's movie once, they was a comical sketch of India sending an astronaut to the moon. At the last moment, the planned launch was cancelled by an astrologer as it was the day of the new moon amavasay, hence it was not visible, so no where to go!