I think a big reason for this is that PDF editing tools are just pretty terrible.

PDFs are meant to be a presentation document format, not an editable document format. I have some experience editing PDFs, and it's difficult to make significant modifications. Editing small sections of text or replacing a date is fine, but once you try to start editing entire paragraphs or changing the layout, it quickly becomes unmanageable. The kerning looks weird, the spacing between words looks off, and when you look into it you realize the the sentence you're trying to edit is actually split across a dozen text objects. For these it becomes almost impossible to edit without destroying the spacing, so you just give up.

And the approved way to edit these PDFs is via Adobe Acrobat Pro, which costs $20/month (ugh), which I'm not willing to pay for.

So I think this is why we just don't see that many PDF forgeries. The editing tools just aren't very good. Maybe it's different now we can just ask Claude to edit our PDFs for us.

I agree that you won't find forged PDF documents in the wild with any type of frequency, but they are forged in private settings. Forged or doctored bank statements are relatively more common. FinCEN identifies altered bank statements alongside W-2s, tax returns, gift letters, and employment information as examples of documents involved in mortgage fraud [1]. In March 2026, a mortgage loan officer was even charged by federal prosecutors with altering and creating bank statements to make borrowers appear qualified for a mortgage [2].

[1] https://www.fincen.gov/mortgage-loan-fraud

[2] https://www.justice.gov/usao-mdfl/pr/licensed-mortgage-loan-...

The flip side to this is that when you do come across a forged PDF (and I have!), they can be really, really effective. Nobody expects them. There are usually tells in the metadata, but... there don't have to be.

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!

I'd say the reason for this is that PDFs are not viral like images or videos. I don't think any of the technical arguments are strong enough.

If you want to forge a PDF, you do it because you have a private target in mind. Financial fraud, corporate espionage... There are other settings but people don't just share PDFs around for you to see a deluge of fake ones.