We use Web Essentials in our Visual Studio project, and we use a main Site.Less file that compiles into Site.css, and Site.css.map & Site.min.css.
Because Less is a new technology to some team members we sometimes get people writing code into the Site.css file and checking that in. Recently we had a week's worth of changes that got overwritten because somebody else changed the Less file, compiled and checked in. Thankfully the history kept the .css changes.
Is there a way to prevent the Site.css file, which is underneath Site.less, from being checked in? This would serve as a reminder that people need to edit the Less file and not the CSS file.