On a site that is version controlled and has a QA workflow for changes, you simply disable the UI for changing those things on production, and the only way to i

On a site that is version controlled and has a QA workflow for changes, you simply disable the UI for changing those things on production, and the only way to influence them is by committing the changes exported as code and deploying. The UI is enabled on development environment, allowing for extremely quick experimentation (possibly by non-technical folk), but you still get (most) of the benefits of changes being in code. ETA: It's not perfect, but it's on it's way to becoming the best of both worlds. Drupal 8 is making significant progress in that direction.