In the wild this tech will get ripped to shreds. The exploits will be endless. And the interesting question is: is it really shoplifting if their system fails to register the sale? Not really, so it is open season.
1) They can have people review recordings for items that the system is less than sure of and charge the customer accordingly.
2) They could ban customers from the store if they determine that the customer seems to be attempting to subvert the system.
Customers already steal things from stores. In this case, the fact that you have to tap-in makes it a lot less of an anonymous shopping experience which would likely deter people from trying to cheat the system. If people are trying to cheat the system, it seems relatively easy to ban them (compared to a conventional store).
Amazon doesn't need to solve everything. Today, if you claim that you didn't receive a delivered package, what does Amazon do? I'm guessing that they just send another. However, I'd also guess that there's some trigger noting, "this person seems to have way more packages stolen than we'd expect". At that point, you can take action like requiring signatures or shipping to an Amazon locker.
Similarly, Amazon will accept a certain amount of loss combined with the ability to note over time what is going on. The automated system may not be perfect, but presumably humans can review recordings.
Ultimately, the only difference between current retail and this is the assumed intent. If someone walks out of a normal store without checking out an item, it's assumed that they intended to steal it. If someone walks out of an Amazon Go without paying, you assume they intended to pay and the system failed. However, if someone is putting their back to goods and picking them up from behind, that's pretty suspicious looking.
It seems like Amazon's surveillance is meant to capture way more than typical retail and that should allow them to find bad actors easier, even if it requires a little human review.
Edit: Other commenters state the sq ft of the store is closer to 1800, still very controllable.
Why wouldn't it be shoplifting here if it is at any other store? If the cashiers and loss prevention officers don't notice you walking out with merchandise in your pocket, is it somehow worse because their eyes and brains are made of flesh instead of plastic and metal?
Worse than a conventional store?
Stores only work right now because most people are honest. AI powered cameras watching you all the time is not going to make shoplifting easier.