Deleting contacts

[angelo-v]

It is unclear to me what it would mean to "delete" a contact. The contact itself being a vcard:Individual cannot be deleted, only documents can. So we have multiple (non-exclusive) options

1. unlink the contact in question from a specific address book, but leave the document in place, because it might be referenced by other address books or other things on the web.
2. (try to) delete the contact document, potentially leaving behind dead links
3. (try to) delete all statements from the contact document
4. leaving a Tombstone in place of the former contact, e.g. something like <#this> a crdt:Tombstone; vcard:fn "deleted" . to prevent dead links

Anyone thoughts on that?