CBS Los Angeles has recently reported that a new law has been signed that will allow Californians to rescue animals trapped in hot cars without fear of prosecution. This allows rescuers to smash car windows to set pets free if they are left unattended in a hot vehicle and there is no other way to rescue them. From their article:
That means rescuers can break into the car if the animal appears to be in peril, the car is locked and law enforcement is not arriving quickly enough.
The rescuer must stay at the scene until law enforcement respond to the situation.