>>48538
>But does Bernd know, that Google crawlers can find a webpage without it being actually linked on another website,

It happens often. Near 10 years ago there was a story that Yandex crawled order information links from some sex shop, and they were easily found by search with some specific options. Reason was yandex browser add-on that sends visiting URL every time. That was fun.

Now it is even easier. Most of sites have some kind of remote analytic software that records everything visited, even if it has no links. Most popular messengers also do link preview and of course remember those links (even when they say they don't). I guess android and chrome send everything to Google anyway.

So any link that is seen by anyone except you may be treated as known for everyone - there is so much ways to leak it.

>BUT. They won't include it among their search hits, until the "owner" of the website explicitly tells them, that he has this google account, and he has that website?

I wouldn't recommend to rely on this behavior (if it is true). There is nothing that prevents search engine from publishing everything it knows.