I was told once by an user that one must have deposited more than his free-rolls winning in order to roll captcha free, but I'm currently at a rate of 1.9:1 of deposits:freerolls and 1.33:1 of deposits:(freerolls+referralcommissions) and still getting captcha. That's unfortunate okay, but they're still offering a great service, just saying.
The amount is still 2 times or more but the threshold for it to be active was increased from 30k on your account to something higher, My guess is 500k, but I haven't had a chance to send my brother some to test it on his account since he is close at 463k. I am at 2.6:1 on my account with 3.16 Mil and the captcha is still gone