The machine learning solution:

* LaneHawk - identifies items in bottom of car [1]

* Everseen - watches object move through a checkout [2] and reports if they are not scanned. In use at Walmart and "5 of the 10 top retailers" now.

* StopLift - also watches checkouts. Recently purchased by NCR.

This problem is on its way to being solved.

[1] https://www.youtube.com/watch?v=wYd7CcInZ28 [2] https://www.theverge.com/2019/6/20/18693324/walmart-ai-camer... [3] https://www.youtube.com/watch?v=L4VR2z2n5Ec