This is VERY, VERY annoying. If the Meetup has done that retarded thing where you cannot RSVP yes unless you have a PayPal account, we should still be allowed to RSVP "No" no matter what device we are using. More importantly (since it's far more common), we need to be able to RSVP "No" when there is a waiting list. The only purpose of the RSVP 'No' is really to get it off of our list of "things I could possibly do today," so without this option it really messes us our ability to choose.