I agree that this is an issue that requires clarification and/or change. So far we deleted and gave a warning for each instance of public meta discussion we saw, including brief mentions of cards people thought were good. Wouldn't a duel with tournamentready decks convey more information than that? And is that even a bad thing? On the one hand, tournament wins should be personal achievements, on the other hand it can be really hard to get into tournaments if you are not allowed to get any help whatsoever and also discussing the possibilities is fun.
As of now, public discussions will be deleted, PMs and casual matches fall under null, not being punished, since we cant follow them anyway, but kind of frowned upon when you announce your intentions publicly. I'd like to collect more opinions on the matter, so if you got an opinion, please post it!