I do not know what were their exact intentions. If someone from Google would like to take a closer look, contact me to have the emails forwarded.

It's like the third party really had no intention of paying 20K, other than to use it as a carrot to dangle in front of the publisher.

Probably some tech support scam thing. It seems to be the biggest business around in shady blackhat circles.

You could push a lot of scareware with an extension with full access to the browser.