Currently, you will see a warning message "No workflow defined for this tracker" when you create a new tracker without copying an existing workflow. However, no warning is shown for roles even if no workflow is defined for the role.

I think it is helpful for inexperienced Redmine admins to show a similar message when they have created a new role without workflow. They can easily know that they should define it.

In my experience, many beginners have difficulty to find that they have to define workflows to make use of newly created roles and statuses.

!{width: 777px; border: 1px solid #ccc;}.no-workflow-warning@2x.png!