ghosting
n.—Gloss: leaving candy at someone’s door, knocking, and then running away before they answer. «In Delafield, Wis., a suburb of Milwaukee, a practice called ghosting is all the rage. In the two weeks leading up to Halloween, neighbors sneak up to houses, ring the doorbell and try to drop off candy without being detected.» —“Where the Jack-o’-Lanterns Are Only the Beginning” by Louise Kramer New York Times Oct. 21, 2007. (source: Double-Tongued Dictionary)
“Ghosting” also conveys stealthy or covert movement, much like “shadowing”. The term is more and more frequently being used in genre fiction, especially action and sci-fi.