Despite the vaguely militant-underground name "Black Hat", it's a conference of mainstream security researchers, run by a large media firm (CMP Media, which also runs the Game Developer's Conference, and owns a bunch of magazines like InformationWeek). Many of the attendees are themselves in government positions, or serving as contractors. So I'm not sure I'd expect a particularly strong backlash. Heck, some attendees could well be in a position to have already known some of the things that were leaked.