Exhibitionist?

On my way back to work this afternoon, I was walking along my usual path towards the Library. It is exceptionally busy at this time of the day. The Capitol Hill Club has added valet parking to help ease the congestion along 1st Street. I thought I noticed something peculiar about a woman who was walking about a block in front of me. She was in between two other ladies. In between us were several people walking in the same direction- probably noticing the same thing I was. Once I realized what was happening, I was totally aghast and horrified to see that the hem of her skirt was tucked in to her waistband, and her behind was in full view- it was almost like a curtain was pulled open to show the goods. What was exposed was black pantyhose, and no underwear. I was so embarrassed by what I saw, I did not have time to take a picture (nor did I think it was even appropriate). Rather, I ran about a block, excused myself to her, told her that her skirt was pulled up, and then pulled it down. Her response was neither one of shock, embarrassment, or even a thank you for letting me know.... she simply stated "oh- not again?" Some people should not be allowed to wear skirts... or did she do it on purpose? In this town, I wouldn't be surprised. Now I wish I did take a picture- but she probably would not have minded that either.