I have a vision of a grocery checkout system that doesn't currently exist but could easily exist with today's technology. Take Sam's Club, for instance, in which the following items are believed to be true:
1. You must be a member to shop there
2. You must present your membership card which has a magnetic strip
3. All items sold are packaged and bar-coded.
4. The exact weight of all items being sold could be/or already has been entered into their merchandise system.
5. No items are bagged, although you can box them at the checkout register.
6. There is an attendant at the front door when you enter to check your membership.
7. There is an attendant at the exit door to verify your purchases against your receipt.
To me, it just doesn't make any sense that you as a consumer, shop throughout the store, and put your items into a grocery cart, only to have to take them out upon checkout and then have them put back into your grocery cart. Why not make it more seamless, gather more information about your customers, reduce labor expenditures, and also cut down on self-service theft. It can be done.
The grocery cart that I envision would have a scanner gun attached to the cart. The scanner gun would only become detached when you activated the release mechanism with your membership card. Now, Sam's Club has a record as to what time you showed up at the store which will ultimately allow them to know how long you were in the store to purchase the items that you selected which can be further data mined.
Once the scanner gun is activated you would go about your business just as you normally do with the exception being that every time you purchased an item you would scan it in. What happens if you change your mind about a purchase? You could scan it again and select "cancel previous purchase".
What if you forget to scan an item? That's where the weight of the items comes into play. When you checkout you will roll your grocery cart unto a calibrated weight scale. Your cart will be weighed with the products that you have purchased and compared to the estimated weight within a very tight tolerance that the products should come to. If the weight matches within the parameters, you are good to go, and can now select any boxes that you desire to box your goods on the way out with the caveat that perhaps 10% of the time you will be randomly selected for further verification. If the weight doesn't match, your receipt would have to be checked against the items in your cart by an attendant.
Could the system be fooled? That is to say, could you in theory scan in an item with the same weight, but then actually put into your basket a different, but more expensive item that weighs exactly the same? That is, deliberately shoplift? Yes, but that would eventually create an inventory imbalance in which one item sold would be less than what it is suppose to be and another item would be more. Sam's Club would have a computerized list of all purchases of the item that they now have more of, and they also have your membership card ID to match this information to. Upon entering the store again for your next visit, you and innocent others having scanned the same item previously will be more closely
monitored and your chances of being "randomly selected" for an audit of your goods purchased would be significantly higher.
That is why it is best to have this type of checkout system at a Membership only store in which the Terms & Conditions of said membership would spell things out in detail.