Did a google search and found a site that provided information on state laws to protect animals left in vehicles. Only 16 states have such laws (Florida is not one of them) and the laws are written to state that in order to violate the law the conditions have to endanger the animal.
That said, various counties may have laws that the state does not have, so...
https://www.animallaw.info/topic/table-state-laws-protect-animals-left-parked-vehicles
I believe that most RVers are like me. The reason they are not bringing a "pet" along with them but another family member, and are going to take care of them as such.
Don