Victoria De Freese was correct in refusing to hand over her emails. She was applying and affirming both her State and Constitutional Rights.
I've read the Tennessee Open records Act and found this interesting section about emails:
§ 10-7-512. Electronic mail communications systems -- Monitoring of electronic mail communications --
(a) On or before July 1, 2000, the state or any agency, institution, or political subdivision thereof that operates or
maintains an electronic mail communications system shall adopt a written policy on any monitoring of electronic
mail communications and the circumstances under which it will be conducted.
(b) The policy shall include a statement that correspondence of the employee in the form of electronic mail may be
a public record under the public records law and may be subject to public inspection under this part.
Commissioners are not employees of the Mayor, they are representatives of the people, so he cannot request commissioners' records.
Furthermore, if Ms. DeFreese has received emails which were written to her own personal email service, then they are not part of the County's email system. The mayor can only look at emails which were written by employees of the County to the commissioner through the County email address system, but he cannot look at anything that was dispatched or sent via her personal email address - that would trample all over her rights as an American citizen.
Finally, we can now all request the emails of the Sixth floor during the Tyler Harber era...