^^ then if somebody who joined a left game were to win it, they would have made free money at 0 risk. new players, even if others have left several times, should still have to bet some money. thus, the pot could be 3x larger than it would have been, if enough players leave and join.
a player who picks up a "left" nation pays what that nation is currently worth in a given turn, not the original buy-in. Thus, a player who picks up a nation that is in a weak position pays less than someone taking over a more successful nation in the same game. That's a way to account for the relative strength of position. I've joined games that were originally 50 buy-in and only paid 35

because the nation I took over was relatively weak (England had 3 SCs compared to everybody else's 5 or 6.)