If the bag type has a Return Fee greater than zero, marking the bag Returned (from either bag report, the bag's scan page or the order page) automatically credits that amount to the customer's account balance with the description "BAG #<bag number>", so it's available on their next order. Marking Delivered never credits anything. Bag types flagged Not Returnable can't actually be moved to Returned: the update is silently rejected server-side even if a Mark Bag Returned button or link is visible. On the bag scan page the button itself is hidden for Not Returnable bags; on the reports and the order page the button can still show, but clicking it makes no change (and no fee is credited). Bag fees themselves are charged at checkout based on the bag type; refunds of fees are handled separately from the order.