Btw, It is a crime per Utah state law:
(2) Any person who inflicts upon a child serious physical injury or, having the care or custody of such child, causes or permits another to inflict serious physical injury upon a child is guilty of an offense as follows:
(a) if done intentionally or knowingly, the offense is a felony of the second degree;
(b) if done recklessly, the offense is a felony of the third degree; or
(c) if done with criminal negligence, the offense is a class A misdemeanor.
Utah Code Section 76-5-109
76-10-2202 Leaving a child unattended in a motor vehicle.
(1) As used in this section:
(a) "Child" means a person who is younger than nine years old.
(b) "Enclosed compartment" means any enclosed area of a motor vehicle, including the
passenger compartment, regardless of whether a door, window, or hatch is left open.
(c) "Motor vehicle" means an automobile, truck, truck tractor, bus, or any other self-propelled
vehicle.
(2) A person who is responsible for a child is guilty of a class C misdemeanor if:
(a) the person intentionally, recklessly, knowingly, or with criminal negligence leaves the child in an enclosed compartment of a motor vehicle;
(b) the motor vehicle is on:
(i) public property; or
(ii) private property that is open to the general public;
(c) the child is not supervised by a person who is at least nine years old; and (d) the conditions present a risk to the child of:
(i) hyperthermia; (ii) hypothermia; or (iii) dehydration.
(3) This section does not apply if the person's conduct that constitutes a violation of this section is subject to a greater penalty under another provision of state law.
(4) This section preempts enforcement of a local law or ordinance that makes it an infraction or a criminal offense to engage in the conduct that constitutes a misdemeanor under this section.
(5) Notwithstanding any provision of state law to the contrary, a conviction under this section may not be used by a state or local government entity as grounds for revoking, refusing to grant, or refusing to renew, a license or permit, including a license or permit relating to the provision of day care or child care.
https://le.utah.gov/xcode/Title76/Chapter10/C76-10-S2202_1800010118000101.pdf
Doesn’t make any mention about how bad the persons feels about it afterwards.