itthinx

Activate and the Captcha will appear on the affiliate registration form when the <a href="https://wordpress.org/plugins/captcha/" rel="ugc">Captcha</a> plugin is activated.
Requirements:
<ul>
<li><a href="https://wordpress.org/plugins/affiliates/" rel="ugc">Affiliates</a> or <a href="http://www.itthinx.com/shop/affiliates-pro/" rel="nofollow ugc">Affiliates Pro</a> or <a href="http://www.itthinx.com/shop/affiliates-enterprise/" rel="nofollow ugc">Affiliates Enterprise</a></li>
<li><a href="https://wordpress.org/plugins/captcha/" rel="ugc">Captcha</a></li>
</ul>

Affiliates Captcha

Affiliates, Affiliates Pro and Affiliates Enterprise integration with the Captcha plugin.

Pippin Williamson

Andrew Munro / AffiliateWP

Aubrey Portwood

<blockquote>
This plugin was built to be used in conjunction with <a href="https://affiliatewp.com/" title="AffiliateWP" rel="nofollow ugc">AffiliateWP</a>.
</blockquote>
Like other affiliate plugins, AffiliateWP must be installed on the same domain as your e-commerce system (Easy Digital Downloads, WooCommerce etc) to properly track visits and referrals.
This plugin allows your affiliates to promote any landing page (or site) that exists on a completely separate domain. Simply install this plugin on the external WordPress site and your affiliates can now promote it using the site’s URL and their affiliate ID or username appended (eg /?ref=123 or /?ref=john). If a customer uses the affiliate’s referral URL, any outbound links to your e-commerce store will automatically include the affiliate’s ID or username. If the customer then makes a purchase on your e-commerce store, the proper affiliate will be awarded commission. The affiliate’s ID/username is stored in a cookie so even if the customer moves between pages on your site, the outbound links will still have the affiliate’s ID/username appended.
<a href="https://affiliatewp.com/addons/external-referral-links/" rel="nofollow ugc">More information</a>
What is AffiliateWP?
<a href="https://affiliatewp.com/" title="AffiliateWP" rel="nofollow ugc">AffiliateWP</a> provides a complete affiliate management system for your WordPress website that seamlessly integrates with all major WordPress e-commerce and membership platforms. It aims to provide everything you need in a simple, clean, easy to use system that you will love to use.

AffiliateWP – External Referral Links

Allows affiliates to promote external landing pages by including the affiliate's ID or username in any outbound links to your e-commerce store.

Affiliates Captcha vs AffiliateWP – External Referral Links