I don't mind it in the case of the Prestige, because they clearly state "The Director of. . ." and proceed to list the films of that director, films that were pretty damn good. Nolan's three for three in my opinion, between Memento, Insomnia, and Batman Begins. Why not use it as a selling point for your film?
In the case of Harsh Times, is really vauge and misleading. Most people who think about Training Day think mostly about Denzel's performance. After that, people acknowledge the director, Antoine Fuqua. Those things made the film moreso than the screenwriter, assuming this is the "creator" being referred to in the Harsh Times trailer. See, I'm already drawing a blank on the guy!
I do see what you mean though. Or when its "From the Producers of/Studio That Brought You. . . ." I hate that even more. "Quentin Tarantino Presents. . ." He ain't do s*** on the movie!! All that means is, he thought the movie was cool and convinced Bob and Harvey Weinstein to distribute it.