...he opinion that movie canon and book canon are two very separate things, based on the overwhelming number of (mostly small) differences between the books and the movies. With that in mind, it's my thought that book canon overrides movie canon in situations such as these. In the books it is never, to my knowledge, specifically revealed if Draco had the Dark Mark or not, therefore we (or at least I) cannot officially conclude one way or another whether or not he has it. (another example of books overriding movies in terms of canon would be in the case of Luna's romantic counterpart. The movies would have us believe that it's Neville, but we all know she actually ends up with the grandson of Newt Scamander) With all this having been said, I'm not necessarily sold on the Draco-werewolf theory, however I'm strangely at a loss for any solid argument against it. That might be a first for any sort of Harry Potter fan theory. Well done.