Until someone files a lawsuit and a judge and jury decide the infringement question, it’s all speculative.

Some cases are pretty obvious, but even literal copying isn’t always copyright infringement (e.g., if the material is arguably not eligible for copyright protection).

> No one has to claim copyright infringement for it to be copyright infringement.

That's a little bit like "If a tree falls in the forest but nobody hears it..."

I mean, sure, "theoretically" any number of things can be infringement. But it's obviously a gray area, so it only really matters when somebody brings a suit and a work is found to be legally infringing.

The pirate bay case demonstrated that you don't need to prove a specific instance of infringement, only that occurrence of infringement "somewhere/somehow" was more believable than the alternative theory that no such infringement has happened. It may be enough to demonstrate that infringement is trivial, and then point to user statistics to demonstrate that infringement is more believable than that infringement has never happened.