In their code examples they indicate that this works by:

  1) plugin sets header key
  2) the site servings ads needs to hit an API endpoint to verify 
     the header keys' value before rendering ads.

This seems really oversimplified since ads are spread all over most pages, so it first needs to block rendering to wait for a reply from the API, then each ad needs to be wrapped in a conditional. I wonder how well this works with the ads, since I assume they are not set up for conditional loading.