@m_artist: Yeah, there are also 5-year-old kids and now and then even a grown-up that tell you they have a karate blackbelt (which is impossible on any ryu-legal way) or even a kung fu blackbelt :D (that is funny because in kung fu, they don't have a belt ranking system to represent kyu/dan grades ^_^ ). Also, in certain sports, the blackbelt isn't the highest. In karate, there are five levels of the blackbelt, while in judo, the highest belt (5th dan or so, not sure about that) is white-red.
@Static: Yeah, that was the name of the technique... but I doubt it actually was the idol for the Rurouni Kenshin character... as it's a little girl :P I'll check that twice, though.
For Kiaijutsu, it sounds very foolish for a ninjutsu student, because I tend to fight as quiet and calm as I could be. This saves strenght and'll also confuse your enemy (maybe in combination with ukemi (breath techniques), where you can train hard to not show any breathing, which makes you look quite relaxed even after a fight... can be insanely helpful, as all genjutsu).
Other than that, I can't imagine that screaming can do that much harm that it costs yourself strenght. It may be just me, though, and as I said, I lack of experience on this topic... (what I know is that you can't disable the enemies balance sense (no idea how it's called) by screaming alone, which is the only thing that'd make sense... in my opinion).