Toggle on/off the message preference to block non-contacts

With our cohort of students we have found that some of them will access their message preferences and turn on the setting that blocks non-contacts from messaging them.  I understand they do not want to receive messages from other students, however this also blocks our teachers from messaging them.

An option to turn off the visibility of this option, or alternatively, a method of still allowing teachers to message students even if they turn on the block checkbox would solve the issue.