What you said (if I understand you correctly, you didn’t give any examples) boils down to breaking standards established by the current browsers. The standards that web developers and servers universally follow. If you want to build browser that will not follow standards you might just as well render HTML in non-standars ways. Most pages will not work anyway.
Yep, I started seeing the new silly puzzle based capcha and even after solving it the page often says ‘you’ve been blocked, fuck off’.