question

Our sincere apologies for the confusion on this issue. The issue here was one of confusion between "refresh" and "restore" receipts, and we're fixing all documentation to clarify this. In point of fact, the correct process is to submit the receipt obtained via a call to the restoreCompletedTransactions method of SKPaymentQueue in the Store Kit (https://developer.apple.com/reference/storekit/skpaymentqueue/1506123-restorecompletedtransactions). That receipt will contain updated receipts for all non-consumable purchases made by the player, and so will restore purchases made in another account.

Again though, one thing to bear in mind is that this does provide a hacked client with a way to get multiple instances of non-consumable goods, by hitting the restoreCompletedTransactions call multiple times, and using all those receipts. While this would, ultimately, only cause problems for the player (since it would cause the inventory to fill up with these items if they did this a lot), a safer route would be to only sell virtual currencies (a consumable good) in the iTunes store, and then use that VC to make purchases of digital goods via your game's Catalog (using PurchaseItem). And, of course, the best route is always to make sure you can reliably get the player back to their original account on any device by incorporating alternate authentication systems, like Facebook, Twitch, and Google whenever possible.