[WraithLord]

militarist, that's a good observation. I was referring to out-of-band meta gaming. Meaning using communication channels outside of this game to influence it by meta gaming (like, expose your identity, threaten to retaliate in a different game, whatever).

I think that in game "signs" are not meta gaming and are ok. So if someone attacks you and just takes a few provinces and you don't want to attack back - fine. It's your risk that the aggressor would come back for more. Do with it as you will but it will always stay at the realm of guesswork and would never be comparable to a NAP.

I personally find it way more acceptable in no-diplo game than giving gems or gold. When someone gives you gold you don't have to guess much. Obviously he wants to carry favor. That's even "stronger" diplo than a "hello there neighbor" message.