The first is saying that no matter what your rules are, the internet may at any time show you a clip from the highest rated category and should be treated as such.

The internet may also at any time show you outright banned content, but that's often treated as a separate battle no matter if that's Tiananmen Square (or "content promoting terrorism", although now I'm wondering if the Chinese Communist Party think the former is a subset of the latter?) or sexual acts you're not allowed to show in film (varies by jurisdiction).