It's surprising how some non-programmers cannot wrap their heads around source control. I work in a high-regulated environment, so we produce reams of documentation for a project, and various non-technical members of the team must be able to use our bug tracking system (even for so-called spec defects) and version control.
My current project's manager (the "product manager," who isn't necessarily technical) uses source control, but checks in/adds a new file for each revision. We've tried to explain that's what version control does but he just doesn't get it.