I've heard that Harry Potter is sometimes denounced in some countries, but have never come across it over here. Even the church schools I go into are entirely happy to have it in their libraries. I've never heard such a disclaimer before Buffy or similar shows before (the BBC used to cut Buffy heavily when showing it at tea-time, but for violence, not paranormal activity.) Maybe it was because this was at 2pm on a Saturday, when it could be expected that a lot of children were watching?