Mhm, your microformats are still off somehow Nathan (also having trouble with Parse-This recently but anyway), but no it’s very simple. RSPV is optional. All you gotta do is subscribe to the iCalendar Feed at https://events.indieweb.org/ics/events.ics and visit the events page ~15m before the meetup starts. Link will be available on the events page (or ask on the IRC).
You may login to the events page using IndieAuth, of course 🙂