We don't have any policy on previews. We only have a policy on the latest translated episode. All of the episode.
But sure, I can try to avoid mentioning them in the future in this thread, if I remember to keep myself in check. Not a big deal. I don't make a point of watching them myself, but very often shows boast a real scene still after the ED, sometimes a most significant one, so it's not wise to stop watching when the credits start rolling unless you check the remaining time carefully enough to eliminate the possibility.