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The days of the Good Samaritan are over. First, many aren't inclined to assist or are too cowardly. Second, the criminal element is more ruthless. When they meet resistance, they don't just quit like they used to. They are more and more inclined to challenge all authority, even when cops point guns at them. If you do any more than observe and report, I think you are putting yourself at risk of injury or death.

A Good Samaritan these days can best do their citizen part by observing closely (description, direction of escape, clothing worn, etc) and then reporting it.

My stupid opinion...
 
It's not a dumb policy. Trying to stop a thief could lead to injuries to customers, employees, and bystanders, while also increasing the risk of property damage.

Instead, most companies (including Walmart) make use of their wall-to-wall security footage to ID perpetrators, and then send nasty letters through a collections agency. It's very hard to dodge those (and that is a problem in its own way).

Businesses know what they're doing.

Apple often has plain clothed loss prevention people as well. At least the stores I've been to have them. They're quite obvious.
 
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