passfan:
You are misunderstanding. I am saying that there is only such a requirement if it is indeed written in halacha. But that if there isn’t, then there is no such requirement. That’s it.
As far as when it is and isn’t required, I don’t really know.
The point is, that these horror stories prove nothing. If the hashgacha is following halacha, it doesn’t really matter whether you find a problem one day. Because you were following halacha, and that’s what G-d wants us to do.