Via the Mann himself, the Virginia Supreme Court rejects the proposition that just because you work for a state university, every word you say is public:
“We reject ATI’s narrow construction of financial competitive advantage as a definition of “proprietary” because it is not consistent with the General Assembly’s intent to protect public universities and colleges from being placed at a competitive disadvantage in relation to private universities and colleges. In the context of the higher education research exclusion, competitive disadvantage implicates not only financial injury, but also harm to university-wide research efforts, damage to faculty recruitment and retention, undermining of faculty expectations of privacy and confidentiality, and impairment of free thought and expression. This broader notion of competitive disadvantage is the overarching principle guiding application of the exemption.”
This is indeed a sensible reading; otherwise the public university system is unworkable. Even a modest amount of experience as faculty has shown me that some very sensitive personal information, mostly regarding students, wanders through your email.