[nobody9999]

>I've definitely gotten the sense that the flip side of that is happening - in many cases, items get marked as "shipped" when the label is printed, but often shippers don't hand the package off to the carrier until days later.

AIUI, Amazon's policy is that credit cards don't get charged until the order ships.

As such, some shadier folks will create the label long before the item is actually shipped. However, since the label has been created, the order is now marked as "shipped" and the credit card is charged even though nothing has been packed, let alone actually shipped.