Limit RSVPs or close RSVP block

The RSVP block that can be added to emails for upcoming events makes things so easy, I love it! Previously, our employees were asked to call or email a specific person, but this year we added in this RSVP online feature and have had to chase less people down for their answer; amazing! My only complaint, which I believe to be very valid and relevant, is that a cut-off date and message cannot be added to the back end of the form. Our catering numbers are due a week in advance, so everybody that RSVP'd after the date, I have to personally reach out to and let them know if we can fit them in or not. Which also means I have to check the RSVP report every single day to see if new ones came in.