AMEX told me I could buy as many gift cards as I want at face value (plus postage) using my CC. The fine print says you can't use them for ATMs or casinos (or cruise ships, for some reason), so buying to get the CC miles and then cashing in won't be straightforward (if even practical at all).

For some reason (??) I note that gift cards on eBay generally draw bids below face value (??).

Anyone figured out a workable, reliable, efficient way to churn miles buying and then somehow disposing of/converting gift cards at very close to par value?