B.B.
Just say no. end of story. Just keep in mind though, that no two people are ever alike. What is inapproriate for you could be a non issue in others' homes. But if it's a matter of safety, by all means decline. And remember, it is impossible to ever say "If I were that person, I would..." we all would not, because we will never be that person, and until we are, we would do exactly what we feel others are doing distastefully.