The definition of Event - section 3.1.2., line 691 - is a bit ambiguous: "An event is the report of an effect of which at least one participant has an interest in being aware". Particularly,
1) event is bundled with interaction for no reasons. Are we saying that there are no Events in SOA outside of interaction?
2) event is made equal to a report/message, which contradicts to EDA, and I disagree with this. Events exist regardless reports about it (because reports can totally misrepresent Events)
3) Events happen independently from anybody's interests in them while the messages are always tied with the "interest in being aware" of.
IMHO, Event in SOA is a change in the state of the SOA eco-system; it is a result of an Action, as the text in lines 693 - 695 states already. We cannot say that Event has not happened only based on the fact that nobody was interested in the message about it at the moment of the Event. The Event may be recognised as a later comparison of two states of the SOA eco-system.