Exchange 2013/Outlook 2013 when creating new profile, it adds multiple mailboxes to the new profile

Hello, I have a 2 node Exchange 2013 CU3 DAG in my test environment.  Everything is working fine.. but I noticed if I create a brand new Outlook 2013 profile through autodiscovery where I add my email address and password.. after the profile builds I notice on the left pane of outlook I have 2 additional mailboxes (as though I had manually added them to my profile).  Mow, I do have full mailbox access to those 2 other test mailboxes also.  But I'm puzzled as to why Exchange adds those 2 mailboxes as well to the profile.  Is this something new in Exchange 2013?  Does it search to see what mailboxes permissions I have and add them to the profile automatically? I haven't seen this documented anywhere.. any ideas?