The rapper Fabolous had a hit song "Breathe" several years ago that contained a sample from a Supertramp song. The track leaked and became HUGE before they cleared the sample, so when it came time to negotiate Supertramp had all the leverage. Supposedly they got $100,000 plus almost all royalties, so Fabolous didn't make any money off the single. (Though of course he made tons on album sales).
EDIT: Just because you're supposed to clear samples doesn't mean people always do. If a sample is obscure enough or sufficiently altered, artists may try to get away with it hoping that no one will notice -- apparently that's the case with Daft Punk. I think Timbaland has gotten into trouble sampling foreign artists without permission ("Big Pimpin'", maybe), and the source of the sample in Nas's "Nas is Like" went unknown for around a decade. See http://www.whosampled.com/sample/4061/Nas-Nas-Is-Like-John-V...
"Breathe" by Fabolous: http://www.youtube.com/watch?v=e8zRiaLOkfc
"Crime of the Century" by Supertramp: http://www.youtube.com/watch?v=RLcHStXAaNg (the sampled bit seems to start about 2:07)
For example, if an artist is just posting 80s style tracks with dozens of uncleared samples on their website free for their fans to download, doesn't fair use allow for it?
Eg: https://www.facebook.com/photo.php?fbid=10151547332313143&se...
which is apologising for: http://www.youtube.com/watch?v=BnigNbYVQJE
(This was a massive tune last summer, getting loads of radio airplay and all over the clubs. Hence the apology. Really, by these standards he should apologise to Mr Fingers as well: http://www.youtube.com/watch?v=Xmz3SVuHPhs)
See also: http://www.soundonsound.com/sos/aug11/articles/classic-track...
Also free-gratis isn't co-terminous with non-commercial as - for example - giving away a competing product is a commercial activity. Also moral rights can arguably be harmed by sampling ... and then you've got parody exceptions ... it's nuance all the way down.
Such samples [as in the OP video] IMO aren't substantial but I think the contrary point can be argued well as "if it's not substantial why copy it / it must be substantial to warrant reuse (with or without modification)"?
http://www.slate.com/articles/news_and_politics/jurisprudenc...
Artists like Girl Talk are getting bolder and more blatant in their uncleared sampling. It might have something to do with his giving away his recent albums, though.
Edit: Here's a couple other Slate articles that go into more detail -
http://www.slate.com/articles/business/moneybox/2012/05/adam...
http://www.slate.com/blogs/moneybox/2012/05/08/paul_boutique...
In practice, however, at least big acts always get clearance for the use of samples. That removes the legal uncertainty that would surround a fair use argument.