As you can see from the product in the second link, most skirts should work fine: https://sc01.alicdn.com/kf/HTB11XeAgwaTBuNjSszfq6xgfpXaD/new... (temporary CDN link may expire)

If a pencil skirt is too constricting it could be a problem, but the same can be said for most seated mobile cycle-based transportation methods.