I'm not responsible for training supermarket cashiers, so I don't know exactly what they are required to do. I know that, in the old days when we used to go to supermarkets, cashiers would keep up with the customers and put the items in bags while they ran through the conveyor.
Now, I see that there are plastic bags on the customers' side of the aisle, which to me, is a not-so-subtle hint that the customers are now being encouraged to bag their own groceries. That's an interesting idea, since cashiers now only have to roll an item past a scanner and throw it down the line. If the sensor doesn't make a rude beeping sound or no sound at all, they don't give it a second look. This disturbing trend is exacerbated by chains like The Home Depot and Lowe's who have self-checkout lines. They make us think that it is a convenience to the consumer, when in fact it is a convenience to the retailer, since they don't have to pay cashiers.
While I struggle (comparatively) to place my items in my canvas bags, I must now simultaneously swipe my debit card and enter my PIN and push a few buttons while the items I am paying for pile up on the conveyor belt. All this is happening while the cashier is making small talk with one of her co-workers.
Eventually, I get the processing done and throw the remaining items in my bag. In the meantime, I wonder why it is necessary for a person to be on the other side of the aisle at all. After all, she's just rolling junk over a scanner. The rest of her job is being done by me - free of charge to the supermarket.
It makes me think that perhaps The Home Depot and Lowe's have the right idea.