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...

I really do like old school and I stick with it. I write most of my docs as text in either vi or nano. I neither want nor need formatting beyond the basics. My CV is the only document I own that has formatting, and I used LibreOffice for it. It's a single page.

I had a friend tell me my CV should be in PDF and locked down to prevent recruiters and others from changing it to something other than the original. I know recruiters are fond of changing things up without informing you.

Can you elaborate? Why would they want to change your CV?