This happened in Germany. I am Spanish and I am *not* a lawyer. Of course I have no clue about legal differences with Denmark.
And I am writing from memory.
Years ago, the ailing SCO Group tried to extort money from companies using Linux systems claiming patent infringement.
Curiously, SCO did not specify which patents were being violated. So it was a surreal situation in which the defendant would be unable to fight the case.
If I remember well, a German court ordered them to provide a list of the patents they claimed were being violated or withdraw the claims. It seems that malicious litigation is taken very seriously in German law.
Turns out, SCO withdrew in Germany.
(Added) Groklaw, the website that covered this kerfufle thoroughly, still exists.
http://www.groklaw.net/article.php?story=20071113135529406I have no idea how it is in Denmark, though. But a malicious threat of litigation might be an offense there?
Still speaking as a non lawyer, a patent is a dual edged sword. It provides legal protection against unauthorized use of your invention but it is incompatible with secrecy because, well, patents are published in the first place.