By default the notification of events generated by transition between states are the only way to detect alarm & condition situations. When instances are supported, a client can browse the address space and discover the items that the server considers of interest, such as alarms.
In some systems clients may want to access some aspects of alarm or condition information in manner other than via the event notifications. For example a client may need to know the possible error state an object could encounter. In these systems the server would have to expose Alarm and Condition instances, to allow the client to browse the Alarm and Conditions.