Gizmodo reported today that the RIAA has been asking for the AV vendors to filter for pirated content. You are walking down a slippery slope if you conflate arbitrary content filtering with information security. Anyone who is savvy enough to bootleg media is also savvy enough to disable their AV filter, which would quickly cause the system to become compromised. Additionally, these users are not likely to detect any infection that does occur, leading to yet another system sending out spam and malware. In short, BAD IDEA.