When you type "skirt over pants" into Google, the frequently asked questions are all along the lines of, "Can you wear a skirt over pants?" and "Are dresses over pants in style?" These questions have been posed off and on throughout the years, but the answer varies greatly depending on the time period.
In 2003, for example, the pairing was considered the hight of fashion and a red carpet fixture (particularly, with the Disney Channel crowd). In the years since, it's become something of a taboo, dividing fashion-lovers into two camps: "absolutely love it" or "absolutely hate it."
