The pattern seems to be 2/3 'right' guesses. on sites like eBay, the captcha is broke on firefox. I complete it, and it says "you need to resubmit this form again", and reloads the entire page.
That's the cost of privacy; broken pages and refused access because Google says "NO!".
And businesses are okay with Google denying them money. I wonder if they did a cost/ben analysis if they find it worthwhile.
Thanks to Google, I've actually saved quite a bit of money, they lost out hundreds recently when their automated systems decided to refuse my transaction. Their loss and my gain.