As far as I know, yes. But pinning is not a prerequisite for providing a given piece of content.
Government censors, authorities, copyright trolls, etc can currently get an idea of which nodes are hosting or requesting content the same way anyone else can.
- See who is advertising that they can provide a piece of content
- Try to retrieve the content and see who sends it to you
- Sniff DHT traffic to try to determine who is requesting content