Now Mark, that's not underdressing - you still look smart even though you are wearing slightly fewer items. Underdressing has nothing to do with the number of items but more to do with how close to slovenly your final look is. The top and skirt don't look cheap and nasty so don't be modest.
I never meant that underdressing meant wearing fewer items. I only mentioned not wearing hose as being more casual. In a more formal setting I would always wear hose. The warmer the weather the lower the DEN number. But most of the times I am wearing hose and a higher heel, thus being overdressed when most women (to whom, we are being compared too when skirt wearing) do not wear hose or skirts. Also, typically I would wear a much nicer shirt, as a sleeveless t-shirt is very casual. Most of the times I am wearing a collared shirt, which even for men, is being overdressed as most wear t-shirts these days. The skirt was just a cheap (less than 7€) made of cotton and is loose fitting unlike most skirts I wear. Last time I went to the airport, I was wearing my typical pencil skirt, hose, 4-1/2" pumps, and a collared polo shirt. So, this trip I felt I was underdresssed when compared to my usual outfits.
But back to the topic of this thread, I guess I was still overdressed as most men and women would be wearing t-shirts, pants and sneakers. My wife wore a similar skirt, but flat sandals and a sleeveless blouse. I only saw 2 other women wearing skirts, and both were long below the knee. One was wearing white sneakers (Jeff?) and the other a low wedge heel sandal.