- we've lost the info about "if this option is left unchecked", but it is equally valuable to this audience, isn't it?
- I wouldn't include editorial statements like "unfortunately"
- agree with Adam that casting this in a more positive way is preferable, and that pointing out what they don't have may not be necessary. How about "When you check this option, we recommend that you also check the Auto-Enroll box. That way, the students you enroll will automatically see your course on their dashboards when they log in."