Is it OK to spray the toilet cleaners liquid inside the toilet seat without flushing afterwards?

It is not a good idea to leave any type of chemicals laying around because there is a possibility of poisoning or harming Children, Pets, and Elderly people who are more susceptible to injury. Granted, it would seem like an odd scenario where someone gets harmed but that's why they are called “accidents”. Although these types of products contain either a Basic or Acidic blend of chemicals to perform their function, I doubt it would harm the surface of most commonly used fixtures. It is best to clean up after yourself.