Does it matter how much the GC are?
I personally have done it, never had an order cancelled.
The T&C are clear:
Limitations.
Your Amazon.com Balance cannot be used to purchase other Gift Cards, prepaid open loop cards, or certain third-party gift cards. Gift Cards cannot be reloaded; resold; used for payment outside of
www.amazon.com or its affiliated properties; used for unauthorized advertising, marketing, sweepstakes, promotional or commercial purposes,
including to facilitate the resale or shipment of goods from Amazon.comWe reserve the right, without notice to you, to void Gift Cards (including as a component of your Amazon.com Balance)
without a refund, suspend or terminate customer accounts, suspend or terminate the ability to use our services, cancel or limit orders, and bill alternative forms of payment if we suspect that a Gift Card is obtained, used, or applied to an Amazon.com account (or your Amazon.com Balance is applied to a purchase) fraudulently, unlawfully,
or otherwise in violation of these terms and conditions.
https://www.amazon.com/gp/help/customer/display.html?nodeId=201936990There has been reports on here about Gc being voided.