I do in-person events and book tables based on RSVPs in HB. The only way I know if someone cancels/unRSVPs in HB is by repeatedly checking list the Attendee list manually. Sometimes they cancel on the morning of the event but I have no idea unless I have gone in and checked who's still coming. I would like to get a notification when someone UNRSVPs from an event so I am uptodate in real time on who's coming.