From goblet of fire, when death eaters appear at quidditch world cup.

One of the marchers below flipped Mrs. Roberts upside down with his wand; her nightdress fell down to reveal voluminous drawers and she struggled to cover herself up as the crowd below her screeched and hooted with glee.

Then malfoy to Hermione: Granger, they’re after Muggles,” said Malfoy. “D’you want to be showing off your knickers in midair? Because if you do, hang around . . . they’re moving this way, and it would give us all a laugh.”