While any student may have a cisunix account for the asking, not all students take advantage of this service. The student may not use their cisunix account. To save time and for their convenience, accounts are automatically setup for new students at the start of the fall semester. So while it may appear that you have good coverage for the students that should be on your list, in fact many of these students may not be aware of, or be inclined to use their cisunix account.
Many students come to campus with an e-mail address already established for themselves.
We currently do not have any way of capturing and using this information about a student. We can only detect if a cisunix address exists for a given student and use that address if it does. In the case where the student doesn't have a cisunix account, or has one but doesn't use it, the only solution is to do whatever you can to impress upon these students that e-mail will be an important way for you to keep in touch with them. All of these approaches, of course, will mean having to reach your students via alternate channels to provide this information to them. Student Controlled Subscriptions Students can subscribe themselves to your list using their preferred e-mail account.