I could be wrong, but the timing of the posting of the thread makes me think you're referring to some stuff we spoke about the other night, Makkal.
I don't normally have trouble with this sort of thing (in general
or the specifics from the other night), personally. Do I hear a lot of stuff OOC that my character(s) wouldn't know IC? Sure, but without means or motivation to actually learn that information IC, there's no justification for doing anything about it - and that's enough for me to just go "meh, whatever" and carry on.
For example, a year ago, I knew Silas was going to be outing herself as a Sabik at her party ahead of time. Fair enough, I had been told ahead of time by Silas, but I also had read more than enough in Silas' posts on the IGS to come to the conclusion IC that Silas might be in the closet (so to speak) before he'd told me anything OOC. In this case it was just a confirmation of a suspicion Morwen had IC (and I, OOC), but while she had the means to be suspicious, she lacked the means to confirm it
and any motivation to attempt confirming it, so... she didn't.
End result? Her response to Silas outing herself was literally nothing more than not being surprised.
It's a reasonably safe rule of thumb. If your character lacks the means or motivation to find out the information IC, and lacks the means or motivation to do anything about it, then you don't even need to think about it any further. Obviously, if they do have the means and motivation to do so, you should check with the other player to figure something out before doing anything.
More or less what Laria and Sai have said here.
Also, it's not necessary to leave OOC channels entirely, but you may find a better middle ground with ones that are smaller than or have less traffic than the main ones.