No one knows better than the owner what's best for the toads (assuming the owner is responsible and pays attention to general health and safety). I say it's fine. Generally these "set in stone rules" are more for the newbies who need to know exactly what to do, just to make sure they don't have a bad experience with their first batch of toads from simple mistakes. Like for the people who want to keep their northern water snake in an entirely aquatic setup or for the person who thinks their desert tarantula doesn't need water at a;;. But once you're past the basics stage and have experience and a feel for what works, you have free creative reign.

Good luck.