I look at it like this. If I have to do the job (in person or online) and do everything of a paid employee, then I get 20% off my total bill. Don't get me started on restaurants that add a tip that they decide on the amount to put on your online order.
If I have to do that by myself I'll put stuff in my bag without scanning them, I've done that a few times at Walmart not expensive item's just bird feed suet for the outdoor birds.