Points and Rewards for Failed Orders
When a customer receives an error message about an invalid zip code or credit card details, their points events log shows "Loyalty Points earned for purchase" and "Loyalty Points adjusted for cancelled order" for every time they receive an error message.
Usually customers press the Process Order button multiple times before realizing there is an error, which fills the points events log.
I don't think the log item is useful to the end user. Receiving an error message about an invalid zipcode is not the same a cancelling an order.