What about clicking a checkbox means I'm human? How does Cloudflare determine I'm human from that?
The simplicity of it is logic defying. It used to be that you had to find crosswalks or move puzzle pieces or type blurred letters and numbers, but NOW all the sudden I can just click a box and HEY!, I'm human?
Proof of work, which becomes computationally expensive to scale, along with other heuristics based on your browser and page interaction. I believe it's less about clicking the box and what happens after you've clicked the box.
This is correct. I work in bot detections. There are baseline checks for various browser automation used as bot frameworks like Puppeteer or Playwright. Then there is basic analysis of server side and client side fingerprints; meaning, do the fingerprints you claim make sense. There are other heuristics too and I imagine Cloudflare is monitoring movements that point to automation. All of this happens after you click. I personally prefer this over Google's captcha which frequently doesn't recognize me as a human but is easily bypassed by bots.