Co-op to roll out 'Pay-in-Aisle' app at 30 retail sites

would be interesting to know how a) inventory / stock management is done as the goods purchased are obviously not presented to a scanner of the store anymore and b) how special price offers (e.g. temporarily reduced item price or 3 items for price of 2) are being taken care of ?

In answer to your questions, the app connects to the same stack that runs eCom. Co-op don't have eCom fulfilment centres, items bought online are picked at the local store and then ready for pickup / delivery, so the eCom stack is aware of inventory at each store. 

Still somewhat puzzled ... http://www.retail-systems.com/rs/Co-op_Pay_In_Aisle_Technology_Mastercard.php says '... a new mobile app where customers can checkout their in-store purchases on their phone, without visiting a till.' There (indeed) must be some connection from the app to a 'back-end-inventory-management-system' and I see how price offers are then taken care of. But where scanning a jar of peanut butter at a till / POS unambiguously shows that that jar is leaving the store in question and hence should be 'subtracted' from its inventory, there is no 1:1 relation between the app and the physical location / identification of the store. Bar codes are unique per product (witnessed by the fact that there are apps that allow you to scan a product in store X and it then informs you if that product is cheaper in store Y, Z, ...), so from a bar code one cannot identify the store a product is in; what happens if a customer from store A goes into a store B (from the competition perhaps) and there scans a jar of peanut butter ? If store B supports the same app, which inventory is the jar then subtracted from ?  

Hi, when a customer opens the app he/she will be prompted to check-in, which is done by scanning a QR code displayed on a poster in the store.

The picture is getting complete ... it would be nice if this key-information would be included in an article as published, to help grasping the picture from the start - inherently contributing to the acceptance of the topic (e.g. concept) described.

Practical experiences in supermarkts show that customers do not always (either intentionally or unintentionally) scan all articles they take away or (example) in case the price for a bottle of normal coke, sugarfree coke, lemon coke, .... is the same they just scan one of them a number of times thinking that the bill then shows the correct amount to pay. But not considering at all the consequences for the inventory system. How are these phenomena catered for ?

Very interesting!