If you are a fan of Restaurant Reservations plugin, you might want to secure it by Google’s reCaptcha. The plugin itself doesn’t support it However, implementation is not hard and you could make it just in two steps.
1. Install and setup Invisible reCaptcha for WordPress plugin.
2. Implement a custom form support (for our reservation). Add the following code into functions.php of your child template or use a plugin that allows you to add custom snippets such as Code Snippets. Please, do not add snippets directly into your theme template – you will lose changes in the next theme update.
Done. If you need help, get in touch in comments.