I don't know how much this is true recently, but RS used to be full of microoptimizing incentives which would encourage this kind of behavior, such as incentives tied to average sales size or percent of sales that included particular categories of items that the company wanted to move.

So, I can see why a small ticket sale that would bring down those kind of metrics for an associate would be against that associate's rational self interest, while letting someone walk out of the store with a capacitor -- even though it might make store metrics look worse after the next inventory, and certainly isn't better for the corporation -- would be considered less harmful.