Not to get too involved in this. But "stealth edit" just means you edited without mentioning it.
The general etiquette seems to be to put an "EDIT: " with either an addendum or an explanation of edits you made within your comment.
There is no implied perniciousness or anything, it's called that because you are effectively changing what people have responded to after their response.
An to add to this meta-comment: Remember that someone might have read your post and replied, even if you haven't seen it yet, because you hit "reply" - saw that you needed to do an obvious edit (because there is no preview).
It's sometimes frustrating when you've just realized that you've made a bit of a fool of yourself in the heat of the moment (or in your non-idomatic use of English, and come off as more of an ass-hole (or just more rude) than you might have intended, as might be the case for those of us whose native language isn't English...) -- and then having to explicitly acknowledge in a "edit: whoops, didn't mean to be offensive, sorry"-comment that you did in fact post something a little foolish, rude or just silly.
But, with the high rate of view/replies to some hn-threads, it's better to be safe than sorry, and add a small "edit:"-comment whenever you edit -- even if it's just formatting, grammar or spelling.
The general etiquette seems to be to put an "EDIT: " with either an addendum or an explanation of edits you made within your comment.
There is no implied perniciousness or anything, it's called that because you are effectively changing what people have responded to after their response.