Plus in my opinion, the days of "record sales" are coming to an end... and that if your not releasing music for free, your doing it wrong. Its all gonna end up getting pirated anyway. And when you release music for free, there is no limit to how much or who you can sample, because there in no money involved.
He was put on trial once... And won his case on the very grounds of which the video is talking about... "Fair Use." You can even watch some of the trial on youtube...
In the end... girl talks lawyer played a clip from a girl talk song (it was the part where he mashes together Elton John and Biggie Smalls). The judge ruled it as Fair Use.