In chapter six what does Harry explain about breaking into a home that you haven't been invited into?

He gives several reasons why it isn't a good idea. He explains that it isn't hurtful to wizards but that it will mess up any spells they try to work. For vampires it is very dangerous since they already have trouble staying put together if they live outside the Nevernever. He adds that it is also just rude and he thinks it is wrong.