[Sombre]

I don't think it's as cut and dried as 'did you specify this was a game rule y/n?'

People do expect certain unspecified things. I think basic competency is one of them. Not staling every other turn would be another. Responding to things in the game thread might be another. Very few games specify that you shouldn't purposely suicide your nation, staying in your home province and pillaging to kill as much of the pop as possible before you are eliminated. For some people that might be a legitimate way for them to play, but it's generally taken as given that it isn't ok to do.