PPMN_ — Unclear how to use EntitySnapshot and whether it includes EntityRelationships

It's unclear how to use Snapshot generally, and how the creationDate is supposed to tie in with the Occurrence(s) that updated it.

The scope of a snapshot is not clear, and EntityRelationship is not timestamped in the same way.
If an Occurrence creates and removes some EntityRelationships involving an Entity, how is that represented? ActivityOccurrence::resultingEntityRelationship is not sufficient.