Not quite the scenario described (it wasn't an academic paper), but https://mjg59.dreamwidth.org/73317.html is my experience of dealing with a forged PDF. Part of the reason it's rare is that it's actually very hard to do it well!
Are you saying that RightSignature puts the checksum information inside the document and therefore destroys the checksum? What is the thinking behind that?
was linked in the article!
I believe it's actually linked in the OP about half way down. What a crazy thing for an agent to do - to turn a minor disagreement into a maybe-crime.