Not disagreeing with your first paragraph and will add, that memory management mistakes happen to the best. But it is also probably true, that Google and others

Not disagreeing with your first paragraph and will add, that memory management mistakes happen to the best. But it is also probably true, that Google and others do this, because they know there will always be someone committing shit, no matter, whether they are at Google or another big company. So they want guarantees, not blind trust.