That depends, there is a setting called 'Secure RSVP' and when enabled your attendees must exist on your Attendees List with an email address.
The system attempts to find and RSVP attendees by matching the email they provide with the one in your Attendees List.
If the 'Secure RSVP' setting is disabled, ANYONE can RSVP for this event, this is useful if you want to share a link to RSVP and let your attendees sign up themselves.
Don't Worry, we have your back here too! When someone attempts to RSVP and it fails or generates an error it will be logged as a 'Failed RSVP'.
We show you every failed RSVP and allow you to easily convert that failed RSVP into a attendee on your Attendees List.