There's sort of two problems with this, depending on how you look at it:

1. The capitalist class doesn't value their employees lives, since the cost of an employee dying is a small worker's comp claim and some stolen cash & merch, which is far less than the cost of private security.


2. The people in these neighborhoods have no employment prospects, which makes it easy to find someone to stand in the chalk body outline of the previous cashier, and also makes it predictable that an endless series of hoods will hold up the store.

#2 is really hard to tackle. I'm not sure if UBI would fix it, since you can always supplement your UBI with a Dollar General holdup. It might make Dollar General have to pay more to get people interested in working the cashier side though.

#1 seems like it would respond to a financial incentive, like required life insurance for the cashiers, or an "attractive nuisance" law for running a cash-heavy business with no security.

In Germany, the cheapest drugstore chain with similar problems simply went bust due to them no longer making the cut. It's not really comparable, as you can't expand that easily in Europe, but it certainly shows that this can be regulated:

The rise and fall of the Schlecker empire

How about we get rid of dollar stores and have vending machines instead? It won't cut down on theft, but it would save lives.