> Useful comparison, but to my point: is that sufficient to detect fake entries created by incumbent insiders?

Scandals regarding voter roll fraud are extremely rare. I can only think of one scandal from 2014 where a farmer was alleged to have seasonal laborers register and vote for the party of his wife by mail [1]. In the end, the case against the farmer ended up being tossed on insufficient evidence.

> Also: has that in-person mechanism ever been used by stalkers/abusers to find their hiding targets?

If someone is in hiding and legally protected, it is not allowed to contest these entries [2] since the threshold is very high. For "normal" people, you have to bring clear evidence that fraud may have occurred.

[1] https://www.sueddeutsche.de/bayern/geiselhoering-wahlfaelsch...

[2] https://www.gesetze-bayern.de/Content/Document/BayVV_2021_I_...