Well what one sees when visiting other peoples places is not a reflection of you but a reflection of your childs friend. Its your job to teach your child how to handle said things not how to interpret it if your childs friends shows them something you dont want them to see you should have taught them how to handle it. Yes deny them viewing said things bit ensure they can handle it when they invenitably see it. Prepare them to make decisions themselves not what decicions to make.