(a) The commission may not adopt rules restricting competitive bidding or advertising by a certificate holder except to prohibit false, misleading, or deceptive practices.
(b) In its rules to prohibit false, misleading, or deceptive practices, the commission may not include a rule that:
(1) restricts the use of any medium for advertising;
(2) restricts the use of a certificate holder's personal appearance or voice in an advertisement;
(3) relates to the size or duration of an advertisement by the certificate holder; or
(4) restricts the certificate holder's advertisement under a trade name.