I believe this is why Google, and a few other companies, have started using behavioral analysis to figure out if you are human. Did your mouse wonder around the page before clicking to verify? Did you come from another website as if browsing the web? What device are you using and have you used it on this site before? Are you logged into an account? I’m sure they use many more factors, but it’s something that would be hard to replicate with bot behavior on a consistent basis (for now).