[mkl]

Won't work if they care, as there are other verifications: IP addresses https://developers.google.com/search/apis/ipranges/googlebot..., domain name https://developers.google.com/search/docs/advanced/crawling/...

[account42]

And if Google cared then neither of those pages would be public. At some point SEO became something that Google condoned and actively supported instead of seeing it as people trying to game the system.

[Havoc]

>Won't work if they care,

Indeed. Many have lazy useragent implementations though