Surely in the context of the episode we're talking about: the discovery of the $4M in fraudulent income claimed in the document. In the Word document, that edit would be discoverable. In PDF it is not.
You seem to be making an abstract argument about "PDF security" here. The point of the subthread is a practical point about whether Manafort was correctly generating a fraudulent document or whether he was being a technical rube. He was doing the fraud the right way.
> I am trying to clear up what appear to be hugely misleading assumptions about how PDFs work.
I'm sure you are. But in the process you are spamming an only tangentially related subthread with the clear implication that PDFs store editting history in the way Word documents do (they don't). This is doing the opposite of what you want.
No one here is talking about "editing PDFs" or making PDFs "secure from editting", so your points are only confusing the matter.
The document becomes uneditable by most commonly used PDF readers (Adobe Reader DC, web browsers, etc.). You can still edit it, but changing the actual content becomes substantially more difficult.
Editing a PDF is relatively simple with the appropriate tools, and PDFs are not "flattened" by any of the typical definitions I am familiar with. Numerous PDF editors exist, and the standard is well documented (ISO 32000) and freely published online by Adobe. Signing a PDF is a more effective method to prevent tampering, as compared to relying on people only having PDF readers.
