We are part of a national ( with some international groups in places like Canada and New Zealand). Many of our members find us through our website livingliberally.org and are not on Meetup. So RSVP's bear no relation to the number who attend meetings which ranges from 8 to 12 or more.
Also although we are a liberal discussion group, we welcome everyone and will listen to any views unless they are mean-spirited. So feel free to come. It's always fun and innovative.