My reading of the section in red is that this section of the penal code doesn't apply to the passenger, because he doesn't own or control the vehicle, therefore, he doesn't get the protections in the MPA. (a1) is a protection from UCW by excluding carrying in a vehicle you own or control (like a rental car) from UCW unless you are in violation of (1) and/or (2) or any subsection thereof. The passenger would be guilty of UCW, because this section doesn't apply. IMHO, IANAL, etc.(a-1) A person commits an offense if the person
intentionally, knowingly, or recklessly carries on or about his or
her person a handgun in a motor vehicle that is owned by the person
or under the person's control at any time in which:
(1) the handgun is in plain view; or
(2) the person is:
(A) engaged in criminal activity, other than a
Class C misdemeanor that is a violation of a law or ordinance
regulating traffic;
(B) prohibited by law from possessing a firearm;
or
(C) a member of a criminal street gang, as
defined by Section 71.01.
BTW, thanks for quoting the law, I didn't have the opportunity to look it up for the exact wording.