RSVP module question

Hello all,

I'm using the RSVP module for a website I'm developing and I have a question regarding its use. It's Drupal 6.

I'm looking to have other users RSVP for my events (created using the Date & Calendar modules) without actually having to send out the invitations. Kind of like what the Signup module does.

Is there a way to do this with the RSVP module that I'm unaware of? It seems to me like you have to send out the invites first and then the only people who can do the RSVP are the invitees. But I want EVERYONE to be able to RSVP if they want without needing an invite.