Well, suppose 'Jane Doe' is a full-time student, and has a valid Virginia CHP. She has expressed, in writing, her preference to carry for her own personal protection. The administration denies her request to carry. She obeys all policies. Later, she is brutally raped.
She file suit in federal court, alleging the 'No Gun' policy created a danger for her and others like her. This suit invokes the 'State Created Danger' doctrine, and is one of the few ways to circumvent DeShaney. You can look it up if you like. Even though denying students the right to carry is an affirmative act, the Fourth Circuit is unlikely to be helpful.