The instructions on the FAQ read: "only users with permission can make edits". On the site Configuration>Development>Maintenance Mode interface, the instructions read: "only users with the "Use the site in maintenance mode" permission are able to access your site to perform maintenance".
I would clarify the FAQ answer, and point out that all Content Editors have this "Use the site in maintenance mode" permission already, by default.
csgiles@mit.edu
Thanks! We've made the edit you suggested.
9/25/13