Personally, if the author's been dead for longer than I've been alive, and/or the book was published before my grandparents were born, I'm not overly concerned if I happen to pick up a PD title that turns out to not quite fall under Canada's Life+50 rules.
At that point, I figure the estate has made its money off the original books, and I'll happily allocate mine to something else where at least some of the creators are still alive to benefit.
Case in point, my current book is a graphic novel edition of Arthur Conan Doyle's The Hound of the Baskervilles, adaptation and art done by Ian Edgington and I.N.J. Culbard. It's very cartoony in a gritty way (think Mike Avon Oeming on Powers) and an awesome and surprisingly cute take on Holmes' adventures.
I love it and plan on finding the rest at the library and buying the entire series (this one came with a preview of A Study in Scarlet and apparently there are more planned) when the local comic shops have their sales.