SJS, you missed the point of my point. Whether or not you feel the knee may be halachicaly uncovered, the minute part of the knee gets uncovered, the thigh gets revealed as well.
And that is because of simple human biology. The knee is appr. 2″ high and the the thigh is attached to the knee. If you don’t believe me do some research (just kidding) Therefore even if your Rabbi tells you that the knee is not part of the shuk, if the knee does get uncovered, the part of the thigh in the majority of cases gets uncovered as well.
Aderabe, if you don’t believe me, try on your straight skirts which reach your bottom part of your knee and sit in front of a mirror. Check out what gets revealed when you are sitting.
Even if the skirt is very flairy and won’t reveal part of your thigh in front of the mirror, when going up steps and sitting into a car it will definitely reveal part of your thigh, because as I’ve mentioned, the knee is only about 2″ high and unless you’re wearing a skirt made out of cardboard which will stay in one place, your thigh lower thigh WILL become uncovered.