Hmmmm... automated posting to G+. It's a great thought. But I don't know if there's an API one could make use of.
I'm in a different boat with pgMKE because our "web site" is a G+ page and I create events as G+ Events which are a piece of cake to share. But I realize that doesn't fit for everyone, and http://www.postgresql.org/about/events/ is and should always be the central list.
A better method than a manual one from each event's organizer doesn't come to mind at the moment. Any suggestions that would improve upon that are most welcome.