Well, state of the art is what compamies and professionals do ... and when it comes to copy protection, one might argue that they have no really effective measures to protect texts. This would probably render the paragraph ineffective, should there ever be a trial about that. Trying to give the users all the responsibility is exactly that: A nice try.
There are some measures to make it harder for most users to print content:
Restrict Print Function
Knowledgable users will know how to circumvent these measures. And there are no known measures that would restrict anyone from just taking a photo from the screen. That's state of the art.