Contacted their staff...
"All BMW car clubs fall under the BMW International Council. You are welcome to join the BMW CCA and participate in the raffle and driving events. There is no additional charge for members outside the USA."
Basically we are free to join, just pay the standard $48 membership fee.
I'm tempted to join just to enter the 1 in 5000 chance M3/Z4/335 giveaway. That's amazing odds as far as gambling goes.