Amazon does keep track of many seller performance metrics, including cancellation rate. I don't know what the softer penalties are, but they can and do freeze a

Amazon does keep track of many seller performance metrics, including cancellation rate. I don't know what the softer penalties are, but they can and do freeze accounts, which is obviously horrible if it is your primary income. They don't care whether you actually have the item in hand as long as you ship it in a timely fashion.