Unbans or pardons the ip address of someone who was banned on the session before.
{"msg":"unban_ip","instance_guid":"my_session_id_here","unbanip":"?.?.?.?","role_id":"superadmin"}

The server will unban the client's ip address thus allowing them back in:
{"MSG":"unbanned_from_session"}

If the server finds that the client's ip address is not banned:
{"MSG":"banned_ip_not_found"}