This is what happens when it got gusty at the Uchimizu event.
There is even a otaku word to describe the thigh area showing above the socks - the Zettai Ryouiki (絶対領域(ぜったいりょういき)).
Submitted by one of my media comrades who wishes to remain anonymous. He said that he felt "betrayed" because they were wearing shorts instead of knickers...