Restrict Content Pro Math Verification
This is a straightforward add-on for Restrict Content Pro that adds a math verification field to the registration form, thereby preventing bot registrations without driving your users insane with difficult reCaptchas.
You can add a simple arithmetic verification field to your membership registration form with this add-on. The user must accomplish the simple addition problem in order to register.
This extension is designed to completely prevent bot registrations while presenting a human-friendly and easy-to-use registration process, unlike the experience users have when attempting to comprehend difficult reCaptchas.