I tried the demo in two different browsers that I use regularly. On the one that stays logged into my google account, I was not challenged with a captcha. On the other browser, which I use quite a lot but not with my google account, the captcha appears.

I'd think that having a long-standing google account with a normal history of activity would be a good indication that one might be a human. If google is weighting that heavily for this test, that may create a new incentive for spammers and scammers to hijack people's google accounts.

On what page did you tested the new system?

Here you go: https://www.google.com/recaptcha/api2/demo

1. Tested on my normal chrome where I didn't delete any cookies and logged in to my google accounts, and no adblocker running. So plenty of evidence I'm human, with all those cookies from big G.

2. Tested in incognito mode: BAAM: I'm a bot, had to fill out the old captcha!

Wow, that's odd. I checked it out on mobile and they confirmed me human without giving me the images set similarity question.

I don't think they can predict this from the way I touch the screen >.<

So, I tried it. With a Google Account that had ZERO activity for two years. Using a Java program to activate that site.

Passed the CAPTCHA. Without any further verification.

I mean, spammers are going to love it xD