It's merely an observation that the apparent predilection for this type of meta-gaming, illegal, unwanted, or welcomed, may influence the very nature of a singular diplomacy game and it's underlying strategy.
But this isn't a "Oh my, i see meta-gaming, stomp it!" post.
Remove the term from this discussion if you like, I've never liked it either, and personally am not offended by the employment of it in a game, regardless of what "type" of meta-gaming you use. And if you take that as your opinion, you can understand where there are many different forms of meta-gaming, with a loose definition of:
"Anything outside of the game being used to influence the inside of the game."
This would include acknowledging past experience or friendships with another player, doing extensive research on your opponents complete with charts and graphs, and yes, influencing your play based on the uniform understanding that this game is part of a series.
These types of meta-gaming are going to happen, and I accept and intend to utilise them myself. The only thing I wanted to know, and the only reason I created the thread, was to find out if they are encouraged by the maker(s) of the league.