Is acknowledgment important in this case? Should mash-up DJs give credit to the artists they sample, or is it all fair game?

After watching the video about mash-ups, explain your thinking about mash-ups and the ethics of mash-up artists. Some questions to ponder and jump-start your ideas:
Is it a big deal for mash-up DJs to sample the music of artists who came before them? What about it makes it right/wrong?Is acknowledgment important in this case? Should mash-up DJs give credit to the artists they sample, or is it all fair game?Why do you think mash-up DJs create their music this way?Respond:

POST your reasoning to the discussion forum–whose side did you choose and why?
After watching the video about Al Gore, think about the following questions:
Why did Al Gore do this?Is what Al Gore did a big deal or not? Is it dishonest?Is it wrong for a documentary to use a fabricated Hollywood shot to make a point even if there’s science behind it?Does it harm his credibility?What are the consequences?Following your reflection on the above questions consider how big of a deal is Al Gore’s usage of the footage from The Day After Tomorrow?