As usual, Michael Geist has some spot on analysis:
In this particular case, UE demanded that the site use IP addresses to filter out non-Canadian users, arguing that failing to do so infringes both European and Canadian copyright law. It is hard to see how this is true given that the Supreme Court of Canada has ruled that sites such as IMSLP are entitled to presume that they are being used in a lawful manner and therefore would not rise to the level of authorizing infringement. The site was operating lawfully in Canada and there is no positive obligation in the law to block out non-Canadians.Link
As for a European infringement, if UE is correct, then the public domain becomes an offline concept, since posting works online would immediately result in the longest single copyright term applying on a global basis. That can't possibly be right. Canada has chosen a copyright term that complies with its international obligations and attempts to import longer terms - as is the case here - should not only be rejected but treated as copyright misuse.