The volunteer written and supported Feature Assistant Extension for Scoutbook for Chrome and Firefox’s has an RSVP report that will give you a count of Yes/No/Maybe. The report must be run before Scoutbook switches from RSVP to Attendance mode. See Feature Assistant - What is it? for details.
Adding the ability to RSVP for guests is on the list of requested calendar features. We do not know when the calendar will be scheduled for updates.
