Seasoned users can (and do) also notice these cases and email to let us know. And of course we review as many submissions as we can and rescue the good ones that have been caught in software filters.
It's true that some good posts don't get recovered this way. But I'm not aware of an alternative that would fix that without also seriously diluting the quality of HN. Not all, but certainly most of those posts are dead for good reason.
> we review as many submissions as we can and rescue the good ones
Rescuing good submissions is great, I just wish there were a way to somehow rescue good people making bad submissions, so that they start posting good ones instead. (Or at least stop wasting their time.)
It's true that some good posts don't get recovered this way. But I'm not aware of an alternative that would fix that without also seriously diluting the quality of HN. Not all, but certainly most of those posts are dead for good reason.