Yeah, some act took place at that place and time. In the context of Occurrence, probably an act of sampling or collecting, and so one should expect metadata documenting that act (who, how, etc)
As I alluded to in my previous post, it's not clear to me whether the who, how, etc. are intrinsic properties of the Event, or if the "Event" simply represents the single coordinate in 4-D space-time; and the other stuff is more a function of the Occurrence (i.e., more metadata about documenting the tuple of Event+Individual). I can see rational arguments either way. My inclination is that the word "Event" goes beyond merely the space-time coordinate, and implies some sort of "action". As such, my inclination is to define the "Event" as more than just the 4D space-time coordinate, and include who, how, etc. as part of the "action" of the Event.
As is probably obvious, I haven't throught this through extensively yet, so I reserve the right to change my mind.
Rich