Bundesgerichtshof [Federal Court of Justice of Germany], First Civil Section, Sommer unseres Lebens, I ZR 74/12, November 15, 2012

The Court ruled that whoever uses a Wi-Fi router and does not implement the safety standards against third party usage that are commonly accepted at the time the router is bought, is liable for interferences, if third parties abuse this internet access for copy right infringement. A user of a Wi-Fi router has to comply with commonly accepted safety standards at the time she starts using the router independently from the previous occurrence of infringing acts by third parties. The general burden of proof of the identity of the infringer is on the plaintiff. However, when the defendant alleges that she did not cause the infringement, she bears a duty to disclose the circumstances under which such infringement could occur (note that there is no general duty to disclose material facts/discovery in Germany).