From the updated rules thread:

We used to be very lax on the global "no outside contact" rule, but this has tightened up in recent years. Follow the host for exact guidelines as to what exactly you can and cannot do in a particular game - most if not all hosts will have very specific instructions on this front.
I've marked this for over a year, that some time after the 2015 revival hosts began universally shutting down unmonitored private communications, and typically even one or both of night chat and public participation by the dead.

I'm assuming it has to do either with off-site cultural influence or wider theoretical developments...