Many times we just click on recaptcha & its done so we can claim easily without any verification.I still confused why this happens because other time it ask to click random 3-4 pics to pass.
You can just google a description of how Recaptcha v2 works and you'll get an indepth explanation.
Hah, you joking
recaptcha is a safest captcha system in the world
Every captcha has a flaw and Recaptcha is not the safest by far, it's been broken many times and needed updates. There is a constant tug o war between google and crackers.