What is the law regarding riding in a trailer while it is being towed?

• It is allowed if a seasoned driver is riding in the trailer.
• It is only illegal if an underage person is riding in the trailer.
• It is against the law for anyone to ride in a trailer while it is being towed.
  Explanation:

  "It is illegal for any person to ride in a trailer while it is being towed. This law is in place to prevent serious injuries or fatalities, as trailers are not designed to safely carry passengers."
• Anyone can ride in a trailer while it is being towed.