The 'eventClass', 'eventSeverity', and 'eventTime' fields
are meta-data which could be encoded as XML attributes
in the <notification> element. This should be
required, even if the proprietary <eventType> has
some or all of these fields already.
This is why I keep asking the WG:
Are you SURE you want to forbid all XML attributes, forever,
from being included in the <notification> element?
Are you SURE this is not going to ever come up again
as an issue, because this is the only place we can
really put inter-operable meta-data into the notification message?
(All we need is an 'anyAttribute' clause in the <element>
definition...)