Firefox's new JavaScript PDF Viewer pdf.js is really a disaster.
It completely ignores PDF document permissions set by Acrobat Professional and so on.
With Firefox's pdf.js people can freely print any PDF and copy the texts and images.
This was reported as a bug in bugzilla@mozilla but it seems that it is going to be fixed soon.
Bug 792816 -pdf.js doesn't respect document permissions
https://bugzilla.mozilla.org/show_bug.cgi?id=792816
Bug 845302 -Firefox 19.0 pdf viewer ignores pdf encryption
https://bugzilla.mozilla.org/show_bug.cgi?id=845302
Does nobody in Adobe voice one's disagreement about this?