> 2. Ensuring that people who said “I’m going” actually end up going.
Super interested in how people solved/compensated for this problem. The approach I've found works best is to make the event, basically, "open-doors" (i.e., the RSVP is not actually required, chance attendees always welcome), and hope for the best. Someone mentioned personally messaging people but, well, that's a lot of work for something not my dayjob.
Been hosting a weekly meet-up for over a year now and there are some factors which I think contribute to this problem:
A. We set-up an auto-recurring meet-up event. People sign-up for the events happening within the next month; hence they fill-up quickly. However, as more people discover the event, they find them already fully-booked. These people end up booking for the waitlist and/or the next events that are not yet full (i.e., event slots more than one month ahead). This creates a negative feedback loop. (This January, I had sign-ups for up to May!)
B. With a long waitlist from [A] people who signed-up would tend to cancel last-minute. At that point the people in the waitlist have made other plans already and end up a no-show or just canceling too, sometimes after they already got a slot. This, again, creates a negative feedback loop.
This year, aside from open-doors policy, I've started overbooking the event on purpose to combat [B]. It's sort of effective though every week I'm playing the airline overbooking problem. This calendar year, I've only been "overbooked" once. I'm also, naturally, wary of first-timers who might be a nuisance (e.g. but not only: parent's [5] but s/organizers/attendees/) but so far I wouldn't really say that has been a problem. Maybe the type of our meet-up organically filters for it (we're an art hobby group and if you can't sit still just trying to draw for 2h, or are not interested at all in learning about art and drawing, you will have a very awkward 2h).