The STOP cannot be for the smoking ... but, the offense for which the vehicle was stopped does not have to be cited, only articulated. It is possible that the officer made the stop for some other reason but chose to cite only for this offense.
118947. This act shall be known, and may be cited, as the Marco
Firebaugh Memorial Children's Health and Safety Act of 2007.
118948. (a) It is unlawful for a person to smoke a pipe, cigar, or
cigarette in a motor vehicle, whether in motion or at rest, in which
there is a minor.
(b) For the purposes of this section, "to smoke" means to have in
one's immediate possession a lighted pipe, cigar, or cigarette
containing tobacco or any other plant.
(c) A violation of this section is an infraction punishable by a
fine not exceeding one hundred dollars ($100) for each violation.
118949. A law enforcement officer shall not stop a vehicle for the
sole purpose of determining whether the driver is in violation of
this article.