Draco would be easy to miss in the dark - his black robes covered a black shirt, black slacks. Only his pale skin and bright hair stood out in the moonlight, and even then it was easy to mistake him, at first, as a reflection off the water. Second glances generally turned him into a person, though, even in the dark.
He was standing at the edge of the lake, looking out over it. He wondered, absently, if Pansy had somehow seen the words that Astoria had warded so badly in her own journal. If Pansy was meeting him to yell at him, he supposed this was as good a place as any.