> A pirated MP3 or video file

In the first place, piracy is not illegal in Canada. Provisions surrounding copyright violations fall under bill C11, and that's a civil juncture, not a criminal one. So CBSA agents wouldn't be looking for that in the first place, nor would they have any grounds to do anything about it, since they aren't the rightsholders.

And even if they did, they have an interesting burden of proof in proving a given file was obtained via piracy. And what would they do? Detain you indefinitely because they want to "have a discussion" about some pirated Katy Perry song? I would agree that photos of doing drugs could be met with refusal at the border, but be reasonable.

They are looking for what is called "objectionable material". I don't know about Canada but in Australia it would be importing porn, any CP-like looking things (say porn with young Asian females that look like children and they have no means to check their age) and so on. I don't know full definition but basically they can add and remove stuff to this "objectionably material" list. Possessing data listed there is a crime. Recently, in New Zealand the shooter video go onto that list.