Relevance of fault in DelayedDeletable / markForLocalDeletion() #21

I've got a question about DelayedDeletable and two-step deletion from the book.

In markForLocalDeletion(), the first line of the method is:

guard fault || markedForDeletionDate == nil else { return }

I'm not sure why the value of fault matters here, and I can't find any explanations in the book.