A question - the game doesn't place any hard coded limits on where the Japanese army and navy can operate once they join the Entente. This is generally true for all the units on either side in the game. In the past, I have generally adopted a self-imposed house rule to keep all of them in the Pacific. On the one hand, I am wondering if that is over-doing it, since no other nationality in the game faces such restrictions. On the other, I don't want to be gamey.
What have people generally done in PBEM? House rule? Anything goes?