Okla. Stat. tit. 43, § 43-16
Soliciting in or near court house or grounds prohibited
It shall be unlawful for any person to solicit directly or
indirectly within any courthouse, premises or grounds or lots on
which a courthouse may be located in any county within the State of
Oklahoma for himself or for and on behalf of any minister of the
Gospel or other person, the performance of a marriage ceremony.