Does sound like a very fragile workflow (there's no reasonable way to tell a full-history doc from a "publish grade" doc by glancing at the file on the filesystem.
Keeping everything in proper version control (possibly unzipped, to give usable diffs even for office document formats -- or in something like markdown) -- would at least rise the bar a bit -- there'd be different process for sending a single version of a file, and sending all versions of (all) [a] file(s).
I suppose if you're already running an internal mail server, you could just do filtering there, making sure no version/history-rich documents pass out that way...
Keeping everything in proper version control (possibly unzipped, to give usable diffs even for office document formats -- or in something like markdown) -- would at least rise the bar a bit -- there'd be different process for sending a single version of a file, and sending all versions of (all) [a] file(s).
I suppose if you're already running an internal mail server, you could just do filtering there, making sure no version/history-rich documents pass out that way...