IP/subnet reputation. Either someone in your house has a hacked device, or someone in your neighborhood or IP subnet does, or maybe they were used as a residential proxy due to a router with a hardcoded password or something.
funny - the vpn through work gives me lots of verification. At home I don't get that, but cloudflare/edgesuite does block me for browser/extensions I use.
Soon you'll have to prove you're an adult the same way to click through for cookies. Can't wait.
Don't forget having to take a picture of yourself to pass a Recaptcha check. Ideally, that'll be acknowledged as a bad idea and just go away, but we'll see.
Hopefully AI can provide you a usable avatar.
Age verification is a hard line for me, and may be what helps kick my YouTube addiction.
The problem for many sites and apps is that it's basically impossible to tell one from another now.