Antipiratgruppen, a Danish intellectual property protection group, have decided that it's not worth taking people to court for using unlicensed files because, erm, they can't actually prove anything against them:
“It requires very strong and concrete evidence to have these people convicted. We simply could not lift the burden of proof,” said Antipiratgruppen lawyer Mary Fredenslund when explaining the decision to Politiken.
In just a year, four cases against alleged pirates have come before the High Court in Denmark and the overall result for the copyright holders has been negative. Three of the defendants were acquitted due to insufficient evidence, and in the one case where a file-sharer was convicted, the defendant had confessed.
There's something about Fredenslund's statement which suggests she's a bit disappointed that, in order to convict someone of something, you have to prove they've done something. Pesky old fundamental principles of natural justice, eh?