go to the scene just before the yule ball when harry and the others are in the common room. wait until the "Patil" sisters come in and say, "Hi Harry" to harry, then pause.they will be wearing the same outfit as hermione did in the third movie.
Um, so what? Are you saying that 2 (or in this case, 3) people can't EVER wear the same outfit? Just because Hermione wore a particular outfit in one movie, and someone else wore it in another, it isn't a slip-up. It's just a case of girls wearing the same outfit.