Since I am kilted full time, I do not go back to pants just to use my cycle.
I'd be wary about wearing a new top quality kilt, but have used a second hand trad wool kilt regularly on short rides (to town, shopping etc) and find the pleats stand up remarkably well to contact with the saddle. I keep the saddle high, so the cloth gets nowhere near the wheels. In fact there is less of a problem than when driving a car, since I find it very difficult to slide into the driving seat without bunching the pleats. On a cycle, the cloth falls down either side of the saddle, so no problem.
For longer rides, I wear my home made cotton mugs and am quite comfortable especially when regimental.

By the way, I used to feel far more embarrassed wearing close fitting lycra shorts in public than I do in a mug.

Martin,
Grenoble, France