I used to work at a wagecage very similar and they tell people to let criminals walk out with shit and let the cops do their job. It lets them avoid being sued by grieving family members or media fiascos like with the old guy killed at a Home Depot recently, or with the infamous story of Wal-Mart's loss prevention departments being borderline private police forces sometimes, etc.

Of course it doesn't work in places where even walmart is pulling out of like Portland or Chicago.