To search better, try this search string in google "sitepencarry.mywowbb.com intitle:virginia " along with your query (omit the quotes)
But to your question, it isn't illegal. BUT, due to "how things work" they can apply their rules to you if you are student, faculty, staff. IE, they say they will expel you if you are a student on campus and you are caught carrying, they will. Is this legal? Good question.
But if your kids are enrolled and you aren't, I wouldn't see how them "banning" students from carrying would apply to you!
Of course, I am not a lawyer But that is my understanding.