.02 Character of Testimony.

Except when stipulations are filed, the witnesses whose testimony may be desired at a hearing, investigation, or proceeding before the Commission, or before a Commissioner or hearing examiner as authorized by Public Utilities Article, §3-104, Annotated Code of Maryland, shall testify orally and under oath, unless the Commission, Commissioner, or hearing examiner for good cause shown deems it proper in special cases that written evidence, under affidavit or otherwise, be submitted.