Torrents are different than a P2P program like Kazaa because you don't download the entire file from any one person. By only receiving a portion of the data from one person there is no way that the RIAA, etc. could show that you did anything wrong. The most they could prove is that they downloaded a series of zeros and ones from your IP address and then they put those together with others to form a file. Its too suspicious and self-serving to serve as sufficient evidence.