Show up in public places with pajama? A city style or a bad habit?

It seems usual for Shanghai residents to show up with pajamas in pulic places from lanes, stores, super markets to Nanjing Rd, the most famous shopping street. But now with the approaching of EXPO, local authorities began to manifest the persuasion to people from showing up in pulic places with pajamas.

Some people consider that going out with pajamas, though is a habit for Shanghai residents, does not correspond with international etiquette. Now, the EXPO is decided to be held in Shanghai, and therefore, the image of its citizens will be recognized as a part of Chinese clutures for other nations. So, showing up in public places with pajama is apparently an improper habit.

On the contrary, some people think that going out with pajamas never relates to denounces in quality or civilization. Instead of an improper habit, it is just a living custom, and the local authorities have no rights to intervene.

Dear friends, what's your opinions?