http://documentation.magnolia-cms.com/templates/stk/components/form.html

You can add honeypot component to your form page.

• This component offers simple robot-protection.
• This component is hidden by css.

How it works:

1. Robots try to fill all input fields on the page.
2. Honeypot has 'emptyField' validation.
3. When the field is filled, the form is not submited because of validation fail.

This can avoid for example thousands of emails sent by robots after for submission.