That's for clients to interpret with WoT.

The user doesn't sign anything.

In Proof of Place:

- The owner Asserts a Place
- Other entities then Attest to that being valid/invalid
- Users weigh those attestations how they like.

If I don't trust the government then I'll not weight their attestations on given kind types.

More directly in a swer to your question, the Attestations are linked by the Assertion Event (in this case a Place event).