Originally Posted by zlc

Here is my theory/hope, I buy $30k worth of tickets during the double mile promotion, and earn 60k miles, once the billing cycle closes and the miles post, I will cancel the tickets and get the refund, since the refund happened in a billing cycle that's only 1 for 1, the bank will only retract 30k miles, leaving me a net 30k gain. And if the refund post fast enough, I don't have to make any payment.