Whta's the difference between this and robots.txt?

But even in those cases, we don't publicly tout that we can infringe it, right? Going back to the PDF case, what a developer could do at best (in favor of infringement) in this case is to give an ability to do so in a somewhat obscure way, and I guess that's what the Okular people did. Blaming them publicly that they didn't make it conspicuous enough is obviously too much one-sided. This is a complex real-world problem and there's no single perfect answer, either technically or socially.