You know the problem..
A user asks you "Why does my mailbox icon display that I have 4 unread emails, but there are no unread emails in my inbox or folders?"
The answer is often because:
In both cases, documents in these views will not obviously be displayed as unread, yet these documents are being counted in the Notes client unread mark count.
My idea - exclude documents such as Contacts, Meeting Acceptances et al from the unread mark status.