Perhaps the “metadata” they want scrubbed off is information normally contained within MS office documents.
For a Word file (per document inspector) this includes:
Comments, Revisions, Version, and Annotations
Properties and Personal information
Task Pane apps
Collapsed Headings
Custom XML data
Headers, Footers, and watermarks
Invisible content (e.g. white text on white background)
Obviously, if you are sending more information than you think you are, there is risk for you and the company.
I have heard of such information being introduced as evidence in legal disputes. Once distributed it is fair game.
We have iScrub to scrub that stuff out. Looking at your list, the big issue would be if someone could see the progression of drafts and comments. That kind of stuff would definitely be useful in a legal dispute.