I never did anything to join this "club" but started receiving movies, and my credit card was being charged. Of course, I sent the movies back.
I have no idea how they got my credit card number.
What is even more strange is the fact that they were originally billing a credit card that expired 6/30/12, then continued to bill via the replacement card, for which they somehow obtained the new card's expiration date and security code. I had to cancel my credit card yesterday, and hopefully this will end, but I'll have to wait and see if I am refunded any of the charges that I never consented to.