Comment by Slartie
Actually, discount grocers operate on razor-thin margins of 2-4%. If your inaccuracy is geared to the benefit of your customer (because otherwise you'll be out of business due to the regulatory bodies) and thus removes just one percent of that, you suddenly lose a quarter to half of your earnings! And that goes ON TOP of the additional cost incurred with all that computer vision tech.
In addition to that, you'll have the problem of inventory differences, which is often cited as being an even bigger problem with store theft than the loss of valued product. If the inventory numbers on your books differ too much from the inventory actually on the shelves, all your replenishment processes will suffer, eventually causing out of stock situations and thus loss of revenue. You may be able to eventually counter that by estimating losses to billing inaccuracies, but that's another complexity that's not going to be free to tackle, so the 1% inaccuracy is going to cost you money on the inventory difference front, no matter what.
And to add to that, it's not a neutral environment. If there's 1% of scenarios that are incorrect, people will figure out they haven't been billed for something, figure out why, and then tell their friends. Before you know it every teenager is walking into Amazon Fresh standing on one foot, taking a bag of Doritos, hopping over to the Coca Cola stand, putting the Doritos down, spinning 3 times, picking it up again and walking out of store, safe in the knowledge that the AI system has annotated the entire event as a seagull getting into the shop.