For clarification, I suppose it depends on the store.
But I heard like a decade ago from someone working in Banana Republic that they weren't allowed to stop shoplifters, even if the alarm went off, the security guard wasn't allowed to touch them. Not sure if they saw them doing it they could tell them to stop, but they weren't allowed to stop or restrain them in any way if they already did it. I asked her why do they have security for then in the first place, she said she didn't know, made no sense.
Now I've worked stock, checked bags, etc, at various stores way way back when, and yes, we intervened. One of the clothing stores I worked at, two business partners owned a handful, and word was that in one of them, they used to take shoplifters back into the stock room and quite literally beat the shit out of them, then let them go. What were they going to do, go to the police and say that they were stealing and got beat up as a result? Luckily we weren't that extreme, because I couldn't have done that. But that was a time before people sued McDonald's because they spilled their hot coffee on themselves while drinking while driving in the car.
