Originally Posted by MarqFlyer

If you spend the $100,000 on the mile-earning card, and then return the $50,000 on a non-mile-earning card, it appears as though you'd earn 100,000 miles. But here's the catch - the $50,000 refund on the other card won't be given to you in cash, right? As a result, that card issuer would only offset that $50,000 against past (or perhaps future) purchases...meaning that you'd end up having to spend a net $50,000 on that card too.

End result: You'd have spent $150,000, and then returned $50,000, and received a net of 100,000 miles - the same total you'd have if you would have just made all the purchases and returns on the same card.

Am I missing something here?