The following procedure limits the ability of students enrolled in courses, or participants enrolled in Bb organizations from sending email. Instructor or Org Leaders are not impacted by these limitations.
From the Control Panel, click Customization
Select Tool Availability
Scroll down until you see the listing for Email
Click the Drop Menu for the Email listing and select Email Settings,
You will see a list of "groups" that email can be sent to -- for example, "all participants" "all users" etc.
From the column called "Available," deselect the groups you DO NOT want students to have the right to email to