Hi Jerry!
Thanks for getting in touch with us! Let me help you with this topic.
First, please let me note that we are fairly limited in <u>how much support we can give</u> for custom development questions like that.
That said, we always like helping out and at least point users into the right direction as much possible.
We don’t have a guide ourselves to implement reCAPTCHA for RSVPs, however, you can customize the RSVP form by following our Themer’s Guide and copying the src > views > tickets > rsvp.php file into your theme from the Event Tickets plugin.
Additionally, let me point you to the reCAPTCHA documentation as reference > https://developers.google.com/recaptcha/
I hope that helps! 🙂
Best,
Victor