See more photos of Pippa and London Fashion Week. (Tim Whitby/Getty Images)

Poor Pippa! The younger Middleton sister showed up to the Alice Temperley show Monday night at London Fashion Week in one of the designer’s frocks, a “fan dress” retailing for $1,745 (at right).

When she was standing, it fell a respectable three inches above the knee, but when she sat — in the prestigious front row, right at camera level — she had Internet pervs insisting that they saw London, they saw France. . .

Rookie mistake! But how to avoid it? Our colleague Katherine Boyle scoured photos of fashion’s gatekeepers to see how they dress for the perilous front lines:

(Jemal Countess/Getty Images )

Read more, see more photos: Royal Watch: Pippa Commits the cardinal sin of front row style, 9/20/11