Music firm BMG is facing a lawsuit over copyright-infringement notices sent by its anti-piracy partner Rightscorp. The lawsuit comes from American ISP RCN, which has more than 400,000 customers in the US, and focuses on an age-old argument between ISPs and rightsholders. “The central question for this Court’s determination is whether an Internet service provider should be held liable for copyright infringement simply because it provides Internet connectivity to its customers,” claims the lawsuit, according to TorrentFreak. “Both BMG and Rightscorp are wrongly demanding payment from RCN for that alleged infringement, and have clearly expressed their intention to enforce these purported rights.” RCN is also accusing Rightscorp of sending too many notices, while criticising the monitoring technology that powers them. It’s another headache for Rightscorp, for whom legal costs have been contributing to its losses in recent years.