Production of work emails by a public university in response to a facially infirm subpoena did not violate a clearly established constitutional right, as there was no legitimate expectation of privacy in emails which an employer could freely disclose. Dismissal without prejudice to allow a refiling for statutory claims.
http://www2.ca3.uscourts.gov/opinarch/172172p.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.