Parvati looked at the new decree tacked to the front post of Bat Wings and made a face. 'She's kidding, isn't she?' she mumbled to herself. She looked down. She and George routinely wore Muggle clothing because it was easier. She wore robes at the shop, but she left them there when she departed after work. And of course, all of her underthings were Muggle.
Parvati had a mental image of Umbridge's Inquisitorial Squad demanding to see everyone's underclothes to make sure they weren't Muggle.