Does a woman's wearing of an isdal resemble some innovators?

A woman letting down part of her garment to cover her feet is considered a Sunnah if it is a handspan or an arm's length, and it is neither an innovation (bid'ah) nor an imitation (tashabbuh). This is based on the hadith narrated by Umm Salamah regarding the Prophet (peace and blessings of Allah be upon him) concerning this matter.